Count 'em Slopes (Count 'em All 17!)Discrete Mathematics Level 5
A slope grid is a grid that is made by diagonally slicing a regular grid in half, for example, the figure below shows 4 slope grids with dimensions \(1\times1\), \(2\times 2\), \(3\times3\), \(4\times4\) respectively.
Count the total number of quadrilaterals in a \(30\times30\) slope grid (that is, when \(a=30\)).
Clarification: A quadrilateral is a polygon that has 4 sides.