Hypocycloid prove that an epicycloid with "k" cusps moves snugly inside one with "k"+1 cusps. The evolute of a hypocycloid is an enlarged version of the hypocycloid itself, while the involute of a hypocycloid is a reduced copy of itself. The pedal of a hypocycloid with pole at the center of the hypocycloid is a rose curve. The isoptic of a hypocycloid is a hypocycloid. Curves similar to hypocyloids can be drawn with the Spirograph toy. Specifically, the Spirograph can draw hypotrochoids and epitrochoids. The Pittsburgh Steelers' logo, which is based on the Steelmark, includes three astroids (hypocycloids of four cusps).
Johnny Apollo (toy) games) and a plastic machine pistol with the Johnny Apollo name. Marx also offered a miniature playset similar to their Cape Canaveral Playset for kids (most often found in a tin "suitcase" that doubled as a playset). Johnny Apollo (toy) Johnny Apollo is an American toy line from Marx Toy Company featuring two action figure astronauts, first released in 1968 in response to the then current interest in outer space and the US/Soviet Space Race. The astronauts were Johnny and Jane Apollo, stood approximately 8" (20.32 cm) in height and came with a variety of space gear, including helmet, backpack