Drag the corners around! This is basically just my springy triangle project, but it uses a triangle "antifiller" to clone 3 large rectangles OUTSIDE of the triangle so the whole screen is filled except for the triangle. I used Stable Diffusion to generate the image.
All coding by me. Go to to this TurboWarp link for extra epic graphics quality: https://turbowarp.org/833027797?hqpen&size=640x360 (Because Scratch rounds the coordinates of sprites and makes it look a bit less smooth) My dad told me the how to do cross product: (Rx-Qx)●(Ty-Sy)-(Tx-Sx)●(Ry-Qy)