diff --git a/build.c b/build.c
index eaae471b..ed3609e1 100644
--- a/build.c
+++ b/build.c
@@ -871,7 +871,6 @@ void OnBuild(StringList cli_args)
             D_TagListAppend(&perm, &src_files, D_TagFromPath(&perm, Lit("src/asset_cache/asset_cache.c"), D_TagKind_File));
             D_TagListAppend(&perm, &src_files, D_TagFromPath(&perm, Lit("src/mixer/mixer.c"), D_TagKind_File));
             D_TagListAppend(&perm, &src_files, D_TagFromPath(&perm, Lit("src/settings/settings.c"), D_TagKind_File));
-            D_TagListAppend(&perm, &src_files, D_TagFromPath(&perm, Lit("src/space/space.c"), D_TagKind_File));
             D_TagListAppend(&perm, &src_files, D_TagFromPath(&perm, Lit("src/collider/collider.c"), D_TagKind_File));
             D_TagListAppend(&perm, &src_files, D_TagFromPath(&perm, Lit("src/app/app.c"), D_TagKind_File));
             D_TagListAppend(&perm, &src_files, D_TagFromPath(&perm, Lit("src/playback/playback.c"), D_TagKind_File));
diff --git a/src/base/base.h b/src/base/base.h
index a358108e..7e49ad08 100644
--- a/src/base/base.h
+++ b/src/base/base.h
@@ -27,16 +27,16 @@
 #include "base_intrinsics.h"
 #include "base_atomic.h"
 #include "base_fiber.h"
-#include "base_gstat.h"
 #include "base_memory.h"
 #include "base_arena.h"
+#include "base_uid.h"
+#include "base_string.h"
+#include "base_uni.h"
+#include "base_gstat.h"
 #include "base_buddy.h"
 #include "base_math.h"
 #include "base_rand.h"
-#include "base_string.h"
 #include "base_bitbuff.h"
-#include "base_uid.h"
-#include "base_uni.h"
 #include "base_util.h"
 #include "base_incbin.h"
 
diff --git a/src/base/base_arena.h b/src/base/base_arena.h
index 24fdc803..d7d4e3b4 100644
--- a/src/base/base_arena.h
+++ b/src/base/base_arena.h
@@ -1,3 +1,7 @@
+/* ========================== *
+ * Arena
+ * ========================== */
+
 #define ARENA_HEADER_SIZE 256
 #define ARENA_BLOCK_SIZE 16384
 
@@ -14,6 +18,15 @@
  * Equivalent to arena_push but without actually allocating anything or modifying the arena. */
 #define arena_push_dry(a, type) (type *)(_arena_push_dry((a), alignof(type)))
 
+struct arena {
+    u64 pos;
+    u64 committed;
+    u64 reserved;
+#if RTC
+    b32 readonly;
+#endif
+};
+
 struct arena_temp {
     struct arena *arena;
     u64 start_pos;
@@ -102,14 +115,6 @@ INLINE void arena_reset(struct arena *arena)
     arena_pop_to(arena, 0);
 }
 
-INLINE struct string arena_to_string(struct arena *arena)
-{
-    struct string b;
-    b.text = arena_base(arena);
-    b.len = arena->pos;
-    return b;
-}
-
 INLINE void *_arena_push_dry(struct arena *arena, u64 align)
 {
     u64 aligned_start_pos = (arena->pos + (align - 1));
diff --git a/src/base/base_atomic.h b/src/base/base_atomic.h
index 96b816e2..69d2cb55 100644
--- a/src/base/base_atomic.h
+++ b/src/base/base_atomic.h
@@ -1,3 +1,57 @@
+/* ========================== *
+ * Atomic types
+ * ========================== */
+
+ /* NOTE: Must be aligned to 32 bit boundary by user */
+struct atomic8 {
+    volatile i8 _v;
+};
+
+/* NOTE: Must be aligned to 32 bit boundary by user */
+struct atomic16 {
+    volatile i16 _v;
+};
+
+struct atomic32 {
+    volatile i32 _v;
+};
+
+struct atomic64 {
+    volatile i64 _v;
+};
+
+/* ========================== *
+ * Cache-line isolated atomic types
+ * ========================== */
+
+struct alignas(64) atomic8_padded {
+    struct atomic8 v;
+    u8 _pad[60];
+};
+STATIC_ASSERT(sizeof(struct atomic8_padded) == 64 && alignof(struct atomic8_padded) == 64);
+
+struct alignas(64) atomic16_padded {
+    struct atomic16 v;
+    u8 _pad[60];
+};
+STATIC_ASSERT(sizeof(struct atomic16_padded) == 64 && alignof(struct atomic16_padded) == 64);
+
+struct alignas(64) atomic32_padded {
+    struct atomic32 v;
+    u8 _pad[60];
+};
+STATIC_ASSERT(sizeof(struct atomic32_padded) == 64 && alignof(struct atomic32_padded) == 64);
+
+struct alignas(64) atomic64_padded {
+    struct atomic64 v;
+    u8 _pad[56];
+};
+STATIC_ASSERT(sizeof(struct atomic64_padded) == 64 && alignof(struct atomic64_padded) == 64);
+
+/* ========================== *
+ * Atomics impl
+ * ========================== */
+
 #if PLATFORM_WINDOWS
 
 FORCE_INLINE i8 atomic8_fetch(struct atomic8 *x) { return (i8)_InterlockedCompareExchange8((char *)&x->_v, 0, 0); }
diff --git a/src/base/base_core.h b/src/base/base_core.h
index 00278680..0ad63ce2 100644
--- a/src/base/base_core.h
+++ b/src/base/base_core.h
@@ -365,95 +365,10 @@ GLOBAL const f64 *_f64_nan          = (f64 *)&_f64_nan_u64;
 #define F32_IS_NAN(x) (x != x)
 #define F64_IS_NAN(x) (x != x)
 
-#define PI              ((f32)3.14159265358979323846)
-#define TAU             ((f32)6.28318530717958647693)
-
-/* ========================== *
- * Atomics
- * ========================== */
-
-/* NOTE: Must be aligned to 32 bit boundary by user */
-struct atomic8 {
-    volatile i8 _v;
-};
-
-/* NOTE: Must be aligned to 32 bit boundary by user */
-struct atomic16 {
-    volatile i16 _v;
-};
-
-struct atomic32 {
-    volatile i32 _v;
-};
-
-struct atomic64 {
-    volatile i64 _v;
-};
-
-/* ========================== *
- * Cache-line isolated atomics
- * ========================== */
-
-struct alignas(64) atomic8_padded {
-    struct atomic8 v;
-    u8 _pad[60];
-};
-STATIC_ASSERT(sizeof(struct atomic8_padded) == 64 && alignof(struct atomic8_padded) == 64);
-
-struct alignas(64) atomic16_padded {
-    struct atomic16 v;
-    u8 _pad[60];
-};
-STATIC_ASSERT(sizeof(struct atomic16_padded) == 64 && alignof(struct atomic16_padded) == 64);
-
-struct alignas(64) atomic32_padded {
-    struct atomic32 v;
-    u8 _pad[60];
-};
-STATIC_ASSERT(sizeof(struct atomic32_padded) == 64 && alignof(struct atomic32_padded) == 64);
-
-struct alignas(64) atomic64_padded {
-    struct atomic64 v;
-    u8 _pad[56];
-};
-STATIC_ASSERT(sizeof(struct atomic64_padded) == 64 && alignof(struct atomic64_padded) == 64);
-
 /* ========================== *
  * Common structs
  * ========================== */
 
-struct arena {
-    u64 pos;
-    u64 committed;
-    u64 reserved;
-#if RTC
-    b32 readonly;
-#endif
-};
-
-struct string {
-    u64 len;
-    u8 *text;
-};
-
-struct string16 {
-    u64 len;
-    u16 *text;
-};
-
-struct string32 {
-    u64 len;
-    u32 *text;
-};
-
-#define UID(hi64, lo64) ((struct uid) { .hi = (hi64), .lo = (lo64) })
-struct uid {
-    u64 hi;
-    u64 lo;
-};
-INLINE b32 uid_eq(struct uid a, struct uid b) { return a.hi == b.hi && a.lo == b.lo; }
-INLINE b32 uid_is_zero(struct uid v) { return v.hi == 0 && v.lo == 0; }
-
 struct image_rgba {
     u32 width;
     u32 height;
@@ -465,192 +380,6 @@ struct pcm {
     i16 *samples;
 };
 
-struct sim_client_handle {
-    u32 idx;
-    u32 gen;
-};
-
-struct sim_ent_id {
-    struct uid uid;
-};
-
-struct space_entry_handle {
-    u64 idx;
-    u64 gen;
-};
-
-struct host_channel_id {
-    u32 gen;
-    u32 idx;
-};
-
-/* ========================== *
- * Tag structs
- * ========================== */
-
-struct sprite_tag {
-    u64 hash;
-    struct string path;
-};
-
-/* ========================== *
- * String utils
- * ========================== */
-
-/* Expand C string literal with size for string initialization */
-#define LIT(cstr_lit) CPPCOMPAT_INITLIST_TYPE(struct string) { (sizeof((cstr_lit)) - 1), (u8 *)(cstr_lit) }
-
-/* Same as `STR`, but works with static variable initialization */
-#define LIT_NOCAST(cstr_lit) { .len = (sizeof((cstr_lit)) - 1), .text = (u8 *)(cstr_lit) }
-
-#define STRING(size, data) (CPPCOMPAT_INITLIST_TYPE(struct string) { (size), (data) })
-
-#define STRING_FROM_POINTERS(p0, p1) (CPPCOMPAT_INITLIST_TYPE(struct string) { (u8 *)(p1) - (u8 *)(p0), (u8 *)p0 })
-
-#define STRING_FROM_STRUCT(ptr) (CPPCOMPAT_INITLIST_TYPE(struct string) { sizeof(*(ptr)), (u8 *)(ptr) })
-
-#define STRING_FROM_ARENA(arena) (STRING((arena)->pos, arena_base(arena)))
-
-/* String from static array */
-#define STRING_FROM_ARRAY(a) \
-    ( \
-        /* Must be array */ \
-        ASSERT(IS_ARRAY(a)), \
-        ((struct string) { .len = sizeof(a), .text = (u8 *)(a) }) \
-    )
-
-/* ========================== *
- * Math types
- * ========================== */
-
-#define V2(x, y) CPPCOMPAT_INITLIST_TYPE(struct v2) { (x), (y) }
-#define V2_FROM_V2I32(v) V2((v).x, (v).y)
-struct v2 {
-    f32 x, y;
-};
-
-struct v2_array {
-    struct v2 *points;
-    u64 count;
-};
-
-#define V3(x, y, z) ((struct v3) { (x), (y), (z) })
-struct v3 {
-    f32 x, y, z;
-};
-
-struct v3_array {
-    struct v3 *points;
-    u64 count;
-};
-
-#define V4(x, y, z, w) ((struct v4) { (x), (y), (z), (w) })
-struct v4 {
-    f32 x, y, z, w;
-};
-
-struct v4_array {
-    struct v4 *points;
-    u64 count;
-};
-
-#define V2I32(x, y) CPPCOMPAT_INITLIST_TYPE(struct v2i32) { (x), (y) }
-struct v2i32 {
-    i32 x, y;
-};
-
-#define V3I32(x, y, z) CPPCOMPAT_INITLIST_TYPE(struct v3i32) { (x), (y), (z) }
-struct v3i32 {
-    i32 x, y, z;
-};
-
-struct xform {
-    struct v2 bx;  /* X basis vector (x axis) */
-    struct v2 by;  /* Y basis vector (y axis)*/
-    struct v2 og;  /* Translation vector (origin) */
-};
-
-struct mat4x4 {
-    union {
-        struct { struct v4 bx, by, bz, bw; };
-        f32 e[4][4];
-    };
-};
-
-#define RECT(_x, _y, _width, _height) (struct rect) { .x = (_x), .y = (_y), .width = (_width), .height = (_height) }
-#define RECT_FROM_V2(_pos, _size) (struct rect) { .pos = (_pos), .size = (_size) }
-struct rect {
-    union {
-        struct { f32 x, y, width, height; };
-        struct { struct v2 pos, size; };
-    };
-};
-
-INLINE b32 rect_eq(struct rect r1, struct rect r2) { return r1.x == r2.x && r1.y == r2.y && r1.width == r2.width && r1.height == r2.height; }
-
-struct aabb {
-    struct v2 p0, p1;
-};
-
-/* Values expected to be normalized 0.0 -> 1.0 */
-#define CLIP_ALL ((struct clip_rect) { { 0.0f, 0.0f }, { 1.0f, 1.0f } })
-struct clip_rect {
-    struct v2 p0, p1;
-};
-
-#define QUAD_UNIT_SQUARE (struct quad) { .p0 = V2(0, 0), .p1 = V2(0, 1), .p2 = V2(1, 1), .p3 = V2(1, 0) }
-#define QUAD_UNIT_SQUARE_CENTERED (struct quad) { .p0 = V2(-0.5f, -0.5f), .p1 = V2(0.5f, -0.5f), .p2 = V2(0.5f, 0.5f), .p3 = V2(-0.5f, 0.5f) }
-struct quad {
-    union {
-        struct { struct v2 p0, p1, p2, p3; };
-        struct { struct v2 e[4]; };
-    };
-};
-
-/* (T)ranslation, (R)otation, (S)cale */
-#define TRS(...) ((struct trs) { .t = V2(0,0), .s = V2(1, 1), .r = 0, __VA_ARGS__ })
-struct trs {
-    struct v2 t;
-    struct v2 s;
-    f32 r;
-};
-
-/* ========================== *
- * Collider types
- * ========================== */
-
-struct collider_shape {
-    struct v2 points[8];
-    u32 count;
-    f32 radius;
-};
-
-/* ========================== *
- * Common utilities
- * ========================== */
-
-INLINE u8 min_u8(u8 a, u8 b)     { return a <= b ? a : b; }
-INLINE u8 max_u8(u8 a, u8 b)     { return a >= b ? a : b; }
-INLINE u32 min_u32(u32 a, u32 b) { return a <= b ? a : b; }
-INLINE u32 max_u32(u32 a, u32 b) { return a >= b ? a : b; }
-INLINE u64 min_u64(u64 a, u64 b) { return a <= b ? a : b; }
-INLINE u64 max_u64(u64 a, u64 b) { return a >= b ? a : b; }
-INLINE i32 min_i32(i32 a, i32 b) { return a <= b ? a : b; }
-INLINE i32 max_i32(i32 a, i32 b) { return a >= b ? a : b; }
-INLINE i64 min_i64(i64 a, i64 b) { return a <= b ? a : b; }
-INLINE i64 max_i64(i64 a, i64 b) { return a >= b ? a : b; }
-INLINE f32 min_f32(f32 a, f32 b) { return a <= b ? a : b; }
-INLINE f32 max_f32(f32 a, f32 b) { return a >= b ? a : b; }
-INLINE f64 min_f64(f64 a, f64 b) { return a <= b ? a : b; }
-INLINE f64 max_f64(f64 a, f64 b) { return a >= b ? a : b; }
-
-INLINE u32 clamp_u32(u32 v, u32 min, u32 max) { return v < min ? min : v > max ? max : v; }
-INLINE u64 clamp_u64(u64 v, u64 min, u64 max) { return v < min ? min : v > max ? max : v; }
-INLINE i32 clamp_i32(i32 v, i32 min, i32 max) { return v < min ? min : v > max ? max : v; }
-INLINE i64 clamp_i64(i64 v, i64 min, i64 max) { return v < min ? min : v > max ? max : v; }
-INLINE f32 clamp_f32(f32 v, f32 min, f32 max) { return v < min ? min : v > max ? max : v; }
-INLINE f64 clamp_f64(f64 v, f64 min, f64 max) { return v < min ? min : v > max ? max : v; }
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/base/base_math.h b/src/base/base_math.h
index 777f437f..249e984b 100644
--- a/src/base/base_math.h
+++ b/src/base/base_math.h
@@ -1,6 +1,129 @@
 /* Math functions are default 32 bit (f32, i32, etc) unless specified */
 
-INLINE f32 math_sqrt(f32 x);
+#define PI              ((f32)3.14159265358979323846)
+#define TAU             ((f32)6.28318530717958647693)
+
+/* ========================== *
+ * Math types
+ * ========================== */
+
+#define V2(x, y) CPPCOMPAT_INITLIST_TYPE(struct v2) { (x), (y) }
+#define V2_FROM_V2I32(v) V2((v).x, (v).y)
+struct v2 {
+    f32 x, y;
+};
+
+struct v2_array {
+    struct v2 *points;
+    u64 count;
+};
+
+#define V3(x, y, z) ((struct v3) { (x), (y), (z) })
+struct v3 {
+    f32 x, y, z;
+};
+
+struct v3_array {
+    struct v3 *points;
+    u64 count;
+};
+
+#define V4(x, y, z, w) ((struct v4) { (x), (y), (z), (w) })
+struct v4 {
+    f32 x, y, z, w;
+};
+
+struct v4_array {
+    struct v4 *points;
+    u64 count;
+};
+
+#define V2I32(x, y) CPPCOMPAT_INITLIST_TYPE(struct v2i32) { (x), (y) }
+struct v2i32 {
+    i32 x, y;
+};
+
+#define V3I32(x, y, z) CPPCOMPAT_INITLIST_TYPE(struct v3i32) { (x), (y), (z) }
+struct v3i32 {
+    i32 x, y, z;
+};
+
+struct xform {
+    struct v2 bx;  /* X basis vector (x axis) */
+    struct v2 by;  /* Y basis vector (y axis)*/
+    struct v2 og;  /* Translation vector (origin) */
+};
+
+struct mat4x4 {
+    union {
+        struct { struct v4 bx, by, bz, bw; };
+        f32 e[4][4];
+    };
+};
+
+#define RECT(_x, _y, _width, _height) (struct rect) { .x = (_x), .y = (_y), .width = (_width), .height = (_height) }
+#define RECT_FROM_V2(_pos, _size) (struct rect) { .pos = (_pos), .size = (_size) }
+struct rect {
+    union {
+        struct { f32 x, y, width, height; };
+        struct { struct v2 pos, size; };
+    };
+};
+
+INLINE b32 rect_eq(struct rect r1, struct rect r2) { return r1.x == r2.x && r1.y == r2.y && r1.width == r2.width && r1.height == r2.height; }
+
+struct aabb {
+    struct v2 p0, p1;
+};
+
+/* Values expected to be normalized 0.0 -> 1.0 */
+#define CLIP_ALL ((struct clip_rect) { { 0.0f, 0.0f }, { 1.0f, 1.0f } })
+struct clip_rect {
+    struct v2 p0, p1;
+};
+
+#define QUAD_UNIT_SQUARE (struct quad) { .p0 = V2(0, 0), .p1 = V2(0, 1), .p2 = V2(1, 1), .p3 = V2(1, 0) }
+#define QUAD_UNIT_SQUARE_CENTERED (struct quad) { .p0 = V2(-0.5f, -0.5f), .p1 = V2(0.5f, -0.5f), .p2 = V2(0.5f, 0.5f), .p3 = V2(-0.5f, 0.5f) }
+struct quad {
+    union {
+        struct { struct v2 p0, p1, p2, p3; };
+        struct { struct v2 e[4]; };
+    };
+};
+
+/* (T)ranslation, (R)otation, (S)cale */
+#define TRS(...) ((struct trs) { .t = V2(0,0), .s = V2(1, 1), .r = 0, __VA_ARGS__ })
+struct trs {
+    struct v2 t;
+    struct v2 s;
+    f32 r;
+};
+
+/* ========================== *
+ * Clamping
+ * ========================== */
+
+INLINE u8 min_u8(u8 a, u8 b) { return a <= b ? a : b; }
+INLINE u8 max_u8(u8 a, u8 b) { return a >= b ? a : b; }
+INLINE u32 min_u32(u32 a, u32 b) { return a <= b ? a : b; }
+INLINE u32 max_u32(u32 a, u32 b) { return a >= b ? a : b; }
+INLINE u64 min_u64(u64 a, u64 b) { return a <= b ? a : b; }
+INLINE u64 max_u64(u64 a, u64 b) { return a >= b ? a : b; }
+INLINE i32 min_i32(i32 a, i32 b) { return a <= b ? a : b; }
+INLINE i32 max_i32(i32 a, i32 b) { return a >= b ? a : b; }
+INLINE i64 min_i64(i64 a, i64 b) { return a <= b ? a : b; }
+INLINE i64 max_i64(i64 a, i64 b) { return a >= b ? a : b; }
+INLINE f32 min_f32(f32 a, f32 b) { return a <= b ? a : b; }
+INLINE f32 max_f32(f32 a, f32 b) { return a >= b ? a : b; }
+INLINE f64 min_f64(f64 a, f64 b) { return a <= b ? a : b; }
+INLINE f64 max_f64(f64 a, f64 b) { return a >= b ? a : b; }
+
+INLINE u32 clamp_u32(u32 v, u32 min, u32 max) { return v < min ? min : v > max ? max : v; }
+INLINE u64 clamp_u64(u64 v, u64 min, u64 max) { return v < min ? min : v > max ? max : v; }
+INLINE i32 clamp_i32(i32 v, i32 min, i32 max) { return v < min ? min : v > max ? max : v; }
+INLINE i64 clamp_i64(i64 v, i64 min, i64 max) { return v < min ? min : v > max ? max : v; }
+INLINE f32 clamp_f32(f32 v, f32 min, f32 max) { return v < min ? min : v > max ? max : v; }
+INLINE f64 clamp_f64(f64 v, f64 min, f64 max) { return v < min ? min : v > max ? max : v; }
 
 /* ========================== *
  * Float rounding
@@ -1241,22 +1364,6 @@ INLINE struct quad quad_floor(struct quad quad)
     return res;
 }
 
-/* ========================== *
- * Collider
- * ========================== */
-
-INLINE struct collider_shape collider_from_quad(struct quad quad)
-{
-    struct collider_shape res;
-    res.points[0] = quad.p0;
-    res.points[1] = quad.p1;
-    res.points[2] = quad.p2;
-    res.points[3] = quad.p3;
-    res.count = 4;
-    res.radius = 0;
-    return res;
-}
-
 /* ========================== *
  * Convex polygon
  * ========================== */
diff --git a/src/base/base_string.h b/src/base/base_string.h
index 53353aa7..c1655559 100644
--- a/src/base/base_string.h
+++ b/src/base/base_string.h
@@ -1,8 +1,50 @@
+struct string {
+    u64 len;
+    u8 *text;
+};
+
+struct string16 {
+    u64 len;
+    u16 *text;
+};
+
+struct string32 {
+    u64 len;
+    u32 *text;
+};
+
 struct string_array {
     u64 count;
     struct string *strings;
 };
 
+/* ========================== *
+ * String utils
+ * ========================== */
+
+/* Expand C string literal with size for string initialization */
+#define LIT(cstr_lit) CPPCOMPAT_INITLIST_TYPE(struct string) { (sizeof((cstr_lit)) - 1), (u8 *)(cstr_lit) }
+
+/* Same as `STR`, but works with static variable initialization */
+#define LIT_NOCAST(cstr_lit) { .len = (sizeof((cstr_lit)) - 1), .text = (u8 *)(cstr_lit) }
+
+#define STRING(size, data) (CPPCOMPAT_INITLIST_TYPE(struct string) { (size), (data) })
+
+#define STRING_FROM_POINTERS(p0, p1) (CPPCOMPAT_INITLIST_TYPE(struct string) { (u8 *)(p1) - (u8 *)(p0), (u8 *)p0 })
+
+#define STRING_FROM_STRUCT(ptr) (CPPCOMPAT_INITLIST_TYPE(struct string) { sizeof(*(ptr)), (u8 *)(ptr) })
+
+#define STRING_FROM_ARENA(arena) (STRING((arena)->pos, arena_base(arena)))
+
+/* String from static array */
+#define STRING_FROM_ARRAY(a) \
+    ( \
+        /* Must be array */ \
+        ASSERT(IS_ARRAY(a)), \
+        ((struct string) { .len = sizeof(a), .text = (u8 *)(a) }) \
+    )
+
+
 /* ========================== *
  * Conversion
  * ========================== */
diff --git a/src/base/base_uid.h b/src/base/base_uid.h
index 8e462526..37985748 100644
--- a/src/base/base_uid.h
+++ b/src/base/base_uid.h
@@ -1,3 +1,13 @@
+#define UID(hi64, lo64) ((struct uid) { .hi = (hi64), .lo = (lo64) })
+struct uid {
+    u64 hi;
+    u64 lo;
+};
+
+INLINE b32 uid_eq(struct uid a, struct uid b) { return a.hi == b.hi && a.lo == b.lo; }
+
+INLINE b32 uid_is_zero(struct uid v) { return v.hi == 0 && v.lo == 0; }
+
 struct uid uid_true_rand(void);
 
 struct uid uid_combine(struct uid a, struct uid b);
diff --git a/src/collider/collider_core.c b/src/collider/collider_core.c
index 587ff533..5e4714d8 100644
--- a/src/collider/collider_core.c
+++ b/src/collider/collider_core.c
@@ -69,6 +69,18 @@ INTERNAL struct collider_support_point collider_get_support_point_internal(struc
     return res;
 }
 
+struct collider_shape collider_from_quad(struct quad quad)
+{
+    struct collider_shape res;
+    res.points[0] = quad.p0;
+    res.points[1] = quad.p1;
+    res.points[2] = quad.p2;
+    res.points[3] = quad.p3;
+    res.count = 4;
+    res.radius = 0;
+    return res;
+}
+
 struct collider_support_point collider_get_support_point(struct collider_shape *shape, struct xform xf, struct v2 dir)
 {
     return collider_get_support_point_internal(shape, xf, dir, -1);
diff --git a/src/collider/collider_core.h b/src/collider/collider_core.h
index c751fefd..2fc8451d 100644
--- a/src/collider/collider_core.h
+++ b/src/collider/collider_core.h
@@ -1,3 +1,9 @@
+struct collider_shape {
+    struct v2 points[8];
+    u32 count;
+    f32 radius;
+};
+
 struct collider_support_point {
     struct v2 p;
     u32 i;  /* Index of original point in shape */
@@ -51,6 +57,8 @@ struct collider_closest_points_result {
     struct collider_prototype prototype;
 };
 
+struct collider_shape collider_from_quad(struct quad quad);
+
 struct collider_support_point collider_get_support_point(struct collider_shape *shape, struct xform xf, struct v2 dir);
 
 struct aabb collider_aabb_from_collider(struct collider_shape *shape, struct xform xf);
diff --git a/src/host/host_core.h b/src/host/host_core.h
index 6abe1135..267b059c 100644
--- a/src/host/host_core.h
+++ b/src/host/host_core.h
@@ -30,6 +30,11 @@ enum host_write_flag {
     HOST_WRITE_FLAG_RELIABLE = (1 << 0)
 };
 
+struct host_channel_id {
+    u32 gen;
+    u32 idx;
+};
+
 struct host_cmd {
     enum host_cmd_kind kind;
     struct host_channel_id channel_id;
diff --git a/src/sim/sim.c b/src/sim/sim.c
index 0c7357f7..bd0084cf 100644
--- a/src/sim/sim.c
+++ b/src/sim/sim.c
@@ -4,3 +4,4 @@
 #include "sim_ent.c"
 #include "sim_phys.c"
 #include "sim_step.c"
+#include "sim_space.c"
diff --git a/src/sim/sim.h b/src/sim/sim.h
index 943c4d7e..363e436e 100644
--- a/src/sim/sim.h
+++ b/src/sim/sim.h
@@ -4,12 +4,12 @@
 #include "../base/base.h"
 #include "../sprite/sprite.h"
 #include "../collider/collider.h"
-#include "../space/space.h"
 #include "../host/host.h"
 #include "../mixer/mixer.h"
 
 #include "sim_core.h"
 #include "sim_phys.h"
+#include "sim_space.h"
 #include "sim_ent.h"
 #include "sim_step.h"
 
diff --git a/src/sim/sim_core.h b/src/sim/sim_core.h
index 2e532635..f43f6a32 100644
--- a/src/sim/sim_core.h
+++ b/src/sim/sim_core.h
@@ -11,6 +11,15 @@
 #define SIM_LAYER_RELATIVE_DEFAULT     (0)
 #define SIM_LAYER_RELATIVE_WEAPON      (1)
 
+struct sim_ent_id {
+    struct uid uid;
+};
+
+struct sim_client_handle {
+    u32 idx;
+    u32 gen;
+};
+
 /* ========================== *
  * Startup
  * ========================== */
diff --git a/src/space/space_core.c b/src/sim/sim_space.c
similarity index 100%
rename from src/space/space_core.c
rename to src/sim/sim_space.c
diff --git a/src/space/space_core.h b/src/sim/sim_space.h
similarity index 98%
rename from src/space/space_core.h
rename to src/sim/sim_space.h
index f04e5ae2..6e7f8278 100644
--- a/src/space/space_core.h
+++ b/src/sim/sim_space.h
@@ -1,5 +1,10 @@
 struct space_cell_bin;
 
+struct space_entry_handle {
+    u64 idx;
+    u64 gen;
+};
+
 struct space_entry {
     b32 valid;
     struct space_entry_handle handle;
diff --git a/src/space/space.c b/src/space/space.c
deleted file mode 100644
index 2d6c673c..00000000
--- a/src/space/space.c
+++ /dev/null
@@ -1,3 +0,0 @@
-#include "space.h"
-
-#include "space_core.c"
diff --git a/src/space/space.h b/src/space/space.h
deleted file mode 100644
index dff648e0..00000000
--- a/src/space/space.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#ifndef SPACE_H
-#define SPACE_H
-
-#include "../base/base.h"
-#include "../collider/collider.h"
-
-#include "space_core.h"
-
-#endif
diff --git a/src/sprite/sprite_core.h b/src/sprite/sprite_core.h
index ce6b01db..02508b99 100644
--- a/src/sprite/sprite_core.h
+++ b/src/sprite/sprite_core.h
@@ -12,6 +12,11 @@ struct sprite_startup_receipt sprite_startup(void);
  * Tag
  * ========================== */
 
+struct sprite_tag {
+    u64 hash;
+    struct string path;
+};
+
 INLINE struct sprite_tag sprite_tag_nil(void) { return (struct sprite_tag) { 0 }; }
 
 struct sprite_tag sprite_tag_from_path(struct string path);