Quickly Make Half-Square Quarter-Square Flying Geese & Bonus Triangles. Plus mark perfect seam allowances. Free bonus buddy ruler. Turn fabric strips into perfect half and quarter-square triangles. It’s a cinch with Bonnie K. Hunter’s signature Triangle Tool! Use the printed lines (in two colors) to quickly make HSTs and QSTs in different sizes hourglass units and flying geese. Sew stitch-and-flip triangle blocks from leftover fabric with the Bonus Buddy which doubles as a seam guide for your m