[Aztlan] Maya siege towers?

[Steven Zoraster]

Reading Marisol Cortes Rincon's 2007 dissertation, "A Comparative Study of Fortification Developments Throughout The Maya Region ..." [1], I learned that in the Temple of the Jaguars at Chichen Itza there is a mural showing a Maya siege tower.  Actually, two Maya siege towers.   (page 217 and nearby text). 

I associate siege towers with Assyrians, Romans and Crusaders.  Expensive and requiring sophisticated engineering on the part of the attacking forces.  Is there other evidence for Maya siege towers?   If they were moveable, how is that practical without wheels?  If not moveable, how did they get built inside the range of the defender's projectile weapons?

Steven Zoraster

[1] tinyurl.com/bkyh5e