How do I cast spell just like in Black and White

I was trying to make cast spell system just like in Black and White. Player can create shape using mouse, game detect what kind of shape player did. But I failed to do so. If someone has idea how to do this, please share.

It was more like R&D but it may by useful for someone.

https://www.dropbox.com/s/dnxa6lejcncfwtj/czar.capx?dl=0

There is an old plugin. Dont know if it still works.

There is a simple example, without plugin.