Evodraw

Evodraw is an evolution simulation. True intelligent design. An actual god game. 

Design and draw anything you can imagine. Specify how much the muscles can move Press play and just wait one or two minutes before your creation is crawling  or awkwardly flailing forward.

All your cute horses or indescribable abominations are controlled by a neural network (a Minimal Gated Unit if you're interested). And it learns by an evolutionary algorithm called evolution strategies. 

Here is a video explaining how it works (From a previous version, a lot changed).

Instructions:

Click-Drag the mouse on the background to move the camera.

Click-Drag from the edge of a body part to create a new limb at that point.

Right-Click drag upwards on a body part (you'll see a menu) to draw on only that body part.

Escape: Go back to creature-edit mode.