• 2 sides at 15" × 9 1/4" (full board width)
• 2 treads at 16"
• 1 riser at 16" × 4"

On each side piece, mark a step-shaped notch: 7 1/2" up from the bottom and 4 1/2" in from the front edge. Cut the notch with a jigsaw. Cut a shallow arch in the bottom edge too — it turns the bottom into four "feet" so the stool sits flat on imperfect floors.

Glue and screw the lower tread onto the notches, overhanging the front edge by about 3/4". Pre-drill everything — screws near board ends split wood without pilots.

Glue and screw the top tread across the tops of the sides, then fit the riser vertically under its back edge, screwed into both the tread above and the sides. The riser is what makes the top step rock-solid.

This stool will be used by small people in socks. Round over every edge and corner generously with sandpaper — the finished stool should have no sharp corners anywhere. Finish with paint or a wipe-on poly.