L2L4 (Last 2 Layers, the 4th proposal) is a 3x3 speedsolving method invented by Duncan Dicks in the 1990s. L2Lk (Last 2 Layers, as proposed by Stachu Korick) is an alternate 3x3 speedsolving method developed in late 2010 through 2011.
L2L4 was conceived by Duncan Dicks, who first posted about a series of L2L strategies (L2L1 through L2L4) on the Yahoo! speedsolving group in 2004. Duncan found many algorithms, while Richard Carr also provided several. Dicks himself credited Gustav Fredell for many "improved algorithms for L2L4 making it a much more viable strategy." Dicks set up a website with algorithms. After these initial thoughts, however, there was little to no development.
Recent developments came in 2010 after the method was "rediscovered" on Speedsolving.com. Stachu Korick led the development of L2Lk, publishing documentations for both L2L4 and L2Lk in 2010-2011.
- First, a 1x3x3 block is completed, typically on the D face, and called the "First Layer."
- From this point, each of the LL-specific configurations of CO, CP, EO, and EP are completed, not necessarily separately or in that order.
CO, CP, EO, EP
CO, CP, L2E, ELL
- Once the first layer is done, little thought is needed. Processing and turning speed are both raised at this point.
- High alg-count
- First layer is difficult to optimize.