Programming games have been used as part of puzzle games, challenging the player to achieve a specific result once the program starts operating. An example of such a game is "SpaceChem", where the player must use its visual language to manipulate two waldos as to disassemble and reassemble chemical molecules. In such games, players are able to test and debug their program as often as necessary until they find a solution that works. Many of these games encourage the player to find the most efficient program, measured by the number of timesteps needed or number of commands required. Other similar games include "Human Resource Machine", "SpaceChem", and "TIS-100" were created by Zachtronics, a video game development company known for its puzzle games that implement programming into their game mechanics.