Though Gregor Richards purported 2L as a Turing-complete language with only two operators, the nop operator (that is, anything that's not + or *) is so significant in 2L that it serves as a third. 1L is a family of attempts to reduce the set of symbols even further, producing a two-dimensional language that truly only has two symbols (the name being a perverted joke against 2L: since 2L has 3 commands, 1L has 2 commands).
Several versions of 1L have been proposed and implemented:
- 1L_a, which is fairly pure to the spirit of 1L.
- 1L_AOI, which uses angle-of-incidence to choose actions.
- Black, which was inspired by 1L and BackFlip.
- Wunnel, which combines ideas from 1L with those from turning tarpits.