Multislotting
Multislotting means that when pairing up and inserting one F2L pair we pair up another F2L pair at the same time as we insert the first one.
Multislotting can be applied anytime during the F2L both on adjacent and diagonally placed F2L pairs.
The multislotting algorithms presented here are originally presented by Sébastien Felix, which is one of the top cubers around averaging around 13 seconds. Note that the 82 multislotting algorithms presented here are only a small subset of what you can do with multislotting. However, Sébastien Felix has come up with a very smart way of dividing the presented multislotting cases into eight subgroups.
Some examples to show what multislotting is all about.
Setup your cube with: L' U' R U' R' L
Normally one may intuitively solve the FR corner/edge pair with (R U R') and then continue with U (L' U' L) U' (L' U L) (11,11)
But if we do an L' before the (R U R') trigger we can finish up with U L, i.e. solve with L' (R U R') U L (6,6). For this case we save 5 moves just by adding a single L' before the intuitively (R U R') trigger.
Many of the multisloting subgroups use this type of trick. All the presented multislotting algorithms use simple standard triggers thoughout the entire sequence. Once one understand what 'setup-move' to do the rest of the algorithm is pretty straightforward.
The subgroups are the following:
1. L' (R U R') L - group
2. L' (R U R') U2 L - group
3. L' (R U R') U L - group
4. L' (R U R') U' L - group
5. (R' F R F') - group
6. (R U2 R') - group
7. (R U R') - group
8. (R U' R') - group