Toadette starts out on one side of a wall, where there aren't any Bullet Bills. The ramps leading up the wall are touchstones. Go up the first ramp. Move the ramp above it and you'll find an alcove in it. Stand in it and move the ramp to reach the second gem on the other side. Touch the lowest ramp to move it to this side so the Bullet Bills can't hit you, then drop down. The first gem is on the other side of the lowest ramp. Go up the ramp, then through the doorway to the side you started on for a plant with a Mushroom. Return to the side with the Bullet Bills and walk up the middle ramp. Stand at the top, then move the ramp so you move through the doorway. Walk up the ramp with the Bullet Bills, then drop down to the plant with the third gem. Return to the ramp with the Bullet Bills and run on the narrow path to the Star after the Bullet Bills fire.
Special Challenge: Clear the course in four touches.
To do this, at the start, cross on the diagonal to avoid touching the lowest ramp. Walk up the lowest ramp, go to the Bullet Bill's side, then move the lowest ramp. Touch the middle ramp to move it out of the way, walk up the lowest ramp, then move the middle ramp into place. Stand at the top of the middle ramp and move it to the side you started on, so you move through the doorway. Walk up the ramp with the Bullet Bills and grab the Star.