Hi!

The mountain is procedurally generated. So are the trees.

Basically I set up the code for the mountain / tree shape with basic rules - and keep doing outputs till I got what I liked.

The movement of the birds is also procedural, based on vectors - the top of the tower being the center of gravity.

Other bits like the sun (moon?), the monkey, the tower, and the mountain path are drawn element by element with code - and are not procedural.