Who knew evil mad scientists could be so nice? Lenore and Windell are two of the happiest makers I know. They create beautifully designed kits on their website, such as the flame-decorated Diavolino, a low-cost Arduino-compatible development board, and The Original Egg-Bot Kit, a beginner-friendly CNC art robot.

The evil ones will be back this year at Maker Faire Bay Area, taking place on May 19 and 20 at the San Mateo Fairgrounds to demonstrate their giant-sized recreation of the Digi-Comp II, a mechanical learning calculator kit from the 1960s.

Here’s a video of their Giant Digi-Comp II.