a.k.a. Ride or Walk
Design, copyright, and 3D print by J. A. Storer, 2022.
(plastic, 3 x 4 x 3/8 inches, with cardboard sleeve)

Two simple puzzles in one. The easier version is to remove the two keepers and the s, and then slide the pieces to exchange Nite and Day; it can be done in 30 rectilinear moves. The harder version keeps the s and can be done in 58 rectilinear moves.