feat: Add physics objects with square, circle, and triangle tools

index.html

@@ -20,6 +20,9 @@
                 <button id="tree-seed-btn">Tree Seed</button>
                 <button id="fire-btn">Fire</button>
                 <button id="lava-btn">Lava</button>
+                <button id="square-btn">Square</button>
+                <button id="circle-btn">Circle</button>
+                <button id="triangle-btn">Triangle</button>
                 <button id="eraser-btn">Eraser</button>
             </div>
             <div class="navigation">