(There's no video for Tangram yet. Please contribute to MR and add a video now!)
Tangram lets you make shapes by moving and rotating pre-made triangles on a blank canvas.
You can click and drag corners to rotate and you can move the pieces by drag and drop.
Tangram.sit (8.05 KiB / 8.24 KB)
Tangram / compressed w/ Stuffit
Mac OS 4.x - Mac OS 9.2.2
Emulating this? It should run fine under: Mini vMac