A (two-dimensional) “pyramid” is constructed in four layers: The bottom layer consists of (equally spaced) dots 1, 2, 3, and 4; the next layer includes dots 5, 6, and 7; the following layer has dots 8 and 9; and the top layer has dot 10. You want to invert the pyramid (i.e., bottom layer has one dot and top layer has four) by moving the dots around.

(a) Identify two feasible solutions.

(b) Determine the smallest number of moves needed to invert the pyramid.