a vertex is a corner
notice, #vertices=#sides
we cannot use a circle since it is 1 side but 0 vertices
square,trapezoid, triangle, pentagon, hexagon, octogon
square+triangle is 4+3=7
next is trapezoid which is 4 sides
the shapes can be
trapezoid, square, triangle or
trapezoid, rhombus, triangle or
trapezoid, rectangle, triangle or
rectangle, rhombus, triangle (there are more)