Maths — Parallelograms vs Trapeziums
Counting pairs of parallel sides.
Make it your own.
title "Parallelograms and trapeziums"
set P "Parallelograms"
set T "Trapeziums (exactly one pair)"
only "P" "Two pairs of parallel sides; e.g. rectangle, rhombus, square"
only "T" "Exactly one pair of parallel sides; e.g. right or isosceles trapezium"
intersect "P,T" "Empty (exclusive definition): a shape has either one or two pairs"