Not bad Mike! Actually, I can see 9 faces up to now if we include all profiles. See what I've got: On the sidewalk: 1. The big head: 1 2. The white dressed man: 2 3. The mother's head: 3 4. The baby's head : 4 Over columns: 5. The profile over the right column: 5 6. The three profiles and the face over the left column:9 Mmm, I think the dog is there to trick us!
The dark green triangle is only 2 squares high at it's tallest point. The red one is 3 squares high at it's tallest point. To enable the Orange and the Lime green shapes to stack and not leave any space, the triangle to their left (the one they stack against) must be 3 squares high=the red one.
Answer to the Two Triangles The two shapes are not identical since the two triangles do not have the same slope. The picture of the triangle with the space actually has a bulge on the hypotenuse which takes up one additional square. Test it on graph paper and you will see that the hypotenuse is not a straight line