diff --git a/include/sims.hpp b/include/sims.hpp
new file mode 100644
index 0000000..53c8cd9
--- /dev/null
+++ b/include/sims.hpp
@@ -0,0 +1,14 @@
+#ifndef SIMS_HPP
+    #define SIMS_HPP
+    #include <SDL3/SDL_render.h>
+
+namespace sims {
+    typedef struct {
+        int x;
+        int y;
+        int r;
+    } body;
+    void two_bodies(SDL_Renderer *r);
+}
+
+#endif
diff --git a/src/main.cpp b/src/main.cpp
index 339cabc..41fbbbf 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -4,7 +4,7 @@
 #include <SDL3/SDL_timer.h>
 #include <cstdio>
 #include <cstdlib>
-#include "../include/gfx.hpp"
+#include "../include/sims.hpp"
 
 bool key_event(SDL_Event e) {
     if (e.type == SDL_EVENT_KEY_DOWN) {
@@ -27,6 +27,10 @@ bool event_handling(SDL_Event e) {
     return false;
 }
 
+void sim(SDL_Renderer *r) {
+    sims::two_bodies(r);
+}
+
 int main() {
     if (!SDL_Init(SDL_INIT_VIDEO)){ 
         std::printf("SDL_INIT() failed");
@@ -48,17 +52,13 @@ int main() {
     SDL_Event e;
 
     bool exit = false;
-    struct {
-        int x;
-        int y;
-    } circle_pos;
-    circle_pos = {10, 10};
     while (!exit) {
         exit = event_handling(e);
         SDL_SetRenderDrawColor(renderer, 0, 0, 0, 0);
         SDL_RenderClear(renderer);
-        gfx::draw_circle(renderer, circle_pos.x, circle_pos.y, 10, true);
-        circle_pos.x++;
+
+        sim(renderer);
+
         SDL_RenderPresent(renderer);
         SDL_Delay(16);
     }
diff --git a/src/sims/two_bodies.cpp b/src/sims/two_bodies.cpp
new file mode 100644
index 0000000..36fc926
--- /dev/null
+++ b/src/sims/two_bodies.cpp
@@ -0,0 +1,13 @@
+#include <SDL3/SDL.h>
+#include "../../include/gfx.hpp"
+#include "../../include/sims.hpp"
+
+namespace sims {
+    void two_bodies(SDL_Renderer *r) {
+        body body1 = {10, 10, 10};
+        body body2 = {250, 250, 10};
+
+        gfx::draw_circle(r, body1.x, body1.y, body1.r, true);
+        gfx::draw_circle(r, body2.x, body2.y, body2.r, true);
+    }
+}