Mathematical Sciences Seminar - Rank 3 root systems/Coxeter groups induce (the exceptional) rank 4 root systems/Coxeter groups via a new Clifford spinor construction
https://www.bbk.ac.uk/events/event/4911/mathematical-sciences-seminar-rank-3-root-systemscoxeter-groups-induce-the-exceptional-rank-4-root-systemscoxeter-groups-via-a-new-clifford-spinor-construction