Question: How to animate plots generated using sequence of coordinates?

Imagine three isosceles triangles with coordinates of each stored in a matrix such as:

> coord1:=Matrix(3,2,[0,0,5,0,2.5,4]);

> coord2:=Matrix(3,2,[2,0,7,0,4.5,4]);

> coord3:=Matrix(3,2,[4,0,9,0,6.5,4]);

and plotted together as follows (only the first is shown)

> PLOT(CURVES([[0,0],[5,0],[2.5,4],[0,0]]),COLOR(HUE,1));

I want to create an animation with stationary (original) isosceles triangles in the background along with new isosceles triangles generated by incrementally (say 4 increments) moving only the apex of each triangle until it touches the base of the triangle; obtained by multiplying the apex’s vertical coordinate by (say ¼) in each increment using a do loop. 

Your help is greatly appreciated.

Thank you in advance.