Certain classes of open-ended puzzle games can also support emergent gameplay. The line of games produced by Zachtronics, such as "Spacechem" and "Infinifactory", are broadly considered programming puzzles, where the player must assemble pieces of a mechanism to produce a specific product from various inputs. The games otherwise have no limits in how many components can be used and how long the process needs to complete, though through in-game leaderboards, players are encouraged to make more efficient solutions than their online friends. While each puzzle is crafted to assure at least one possible solution exists, players frequently find emergent solutions that may be more elegant, use components in unexpected fashions, or otherwise diverge greatly from the envisioned route.