diff --git a/physics.jai b/physics.jai
index b60c5d5..10823a4 100644
--- a/physics.jai
+++ b/physics.jai
@@ -4,6 +4,7 @@
 Input :: #import "Input";
 Simp :: #import "Simp";
 
+TIMESTEP: float = 1.0 / 60.0;
 window_width  : s32 = 1280;
 window_height : s32 = 720;
 
@@ -11,7 +12,12 @@ xy :: (x: int, y: int) -> Vector2 {
     return xy(cast(float)x, cast(float)y);
 }
 drawing_in_world_space: bool = false;
-line :: (_from: Vector2, _to: Vector2, width: float = 1.0) {
+WHITE :: Vector4.{1.0, 1.0, 1.0, 1.0};
+GREEN :: Vector4.{0.0, 1.0, 0.0, 1.0};
+drawing_color: Vector4 = WHITE;
+line_thickness: float = 1.0;
+line :: (_from: Vector2, _to: Vector2) {
+    width := line_thickness;
     from := _from;
     to := _to;
     if drawing_in_world_space {
@@ -20,16 +26,21 @@ line :: (_from: Vector2, _to: Vector2, width: float = 1.0) {
     }
     Simp.set_shader_for_color();
     normal := rotate(unit_vector(to - from), PI/2.0);
-    Simp.immediate_quad(from + normal*width, from - normal*width, to + normal*width, to - normal*width);
+    Simp.immediate_quad(from + normal*width, from - normal*width, to + normal*width, to - normal*width, color = drawing_color);
 }
 
 Rect :: struct {
-    pos, halfsize: Vector2; // pos is in world space
-    rotation: float;
+    halfsize: Vector2;
+    pos  , vel      , force : Vector2; // pos is in world space
+    angle, angle_vel, torque: float;
 };
+MASS :: 1.0;
+moment_of_inertia :: (using r: Rect) -> float {
+    return MASS*(halfsize.y*halfsize.y + halfsize.x*halfsize.x)/12.0;
+}
 draw_rect :: (using r: Rect) {
-    facing_to_right := rotate(xy(halfsize.x,0.0), rotation);
-    facing_to_up    := rotate(xy(0.0,halfsize.y), rotation);
+    facing_to_right := rotate(xy(halfsize.x,0.0), angle);
+    facing_to_up    := rotate(xy(0.0,halfsize.y), angle);
 
     upper_right := pos + facing_to_right + facing_to_up;
     upper_left  := pos - facing_to_right + facing_to_up;
@@ -75,16 +86,21 @@ main :: () {
     // Actual render size in pixels can be different from the window dimensions we specified above (for example on high-resolution displays on macOS/iOS).
     window_width, window_height = Simp.get_render_dimensions(window);
 
+    camera.pos = -xy(window_width, window_height)/2.0;
+    camera.zoom = 0.01;
+
     Simp.set_render_target(window);
 
     rects: [..]Rect;
-    array_add(*rects, .{pos = #run xy(0.0,  0.0), halfsize = #run xy(30.0)});
-    array_add(*rects, .{pos = #run xy(40.0, 0.0), halfsize = #run xy(30.0)});
+    array_add(*rects, .{pos = #run xy(0.0,  0.0), halfsize = #run xy(0.3)});
+    array_add(*rects, .{pos = #run xy(1.5, 0.0), halfsize = #run xy(0.3)});
+
 
     quit := false;
     last_time := get_time();
     panning: bool = false;
     last_mouse_pos := mouse();
+    unprocessed_time: float = 0.0;
     while !quit {
         dt := cast(float)(get_time() - last_time);
         last_time = get_time();
@@ -105,25 +121,52 @@ main :: () {
             }
         }
 
-        print("%\n", Input.mouse_delta_z);
         camera.zoom *= 1.0 - 0.1*Input.mouse_delta_z/120.0;
         if panning {
             camera.pos -= mouse_delta;
 
-            //camera.pos -= xy(Input.mouse_delta_x, -Input.mouse_delta_y);
-            
             // this doesn't fix it
             //Input.mouse_delta_x = 0;
             //Input.mouse_delta_y = 0;
         }
 
-        rects[0].rotation += dt * 1.0;
+        // process physics
+        unprocessed_time += dt;
+        {
+            dt: string = "do not use";
+            while unprocessed_time > TIMESTEP
+            {
+                defer unprocessed_time -= TIMESTEP;
+                
+
+
+
+                rects[0].angle += TIMESTEP * 1.0;
+            }
+        }
+
 
         Simp.clear_render_target(0.0, 0.0, 0.0, 1.0);
 
         drawing_in_world_space = true;
+        
+        // draw grid
+        drawing_color = .{0.2, 0.2, 0.2, 0.2};
+        for x: -30..30 {
+            line(xy(x, 30), xy(x, -30));
+        }
+        for y: -30..30 {
+            line(xy(30, y), xy(-30, y));
+        }
+        drawing_color = WHITE;
+
+
+        line_thickness = 2.0;
+        drawing_color = GREEN;
         for rects draw_rect(it);
-        line(xy(0.0, 0.0), screen_to_world(mouse()));
+        line_thickness = 1.0;
+        drawing_color = WHITE;
+        //line(xy(0.0, 0.0), screen_to_world(mouse()));
         drawing_in_world_space = false;
 
         Simp.swap_buffers(window);