World 6 · Bands from a two-site chain · 8 min · PROA gap from alternating hopping
PRO · Crystal Lab
World 6: Bands from a two-site chain is part of PRO
The first world of Crystal Lab is free. PRO opens the other 24 lessons in 8 worlds — simulations, quizzes and all.
PRO includes
- All 26 labs — every world, every lesson
- Practice exams and certificates
$8.33/mo, billed yearly ($99.99) · or $39.99 monthly