Square + circle = lemon

There are sin, cos etc 

There are sinh, cosh etc (hyperbolic)

But we need sins, coss (square), sint, cost (triangle)!

Can you help me to create this animations?

Thanks Fridel.

But!

1. Sorry. It is not Studio Studio but SMath Studio (Russian Mathcad).

2. It is not square but ??? May be a computer or TV screen!

3. Where is one (the) lemon?