// pick a room, a start hour and a duration, then press 📅 Book
day board · 9:00 → 18:00unguarded
room
start
length
needs
overlap test
aStart < bEnd && bStart < aEnd
Three rooms, one day
Pick a room, a start hour and a length, then press 📅 Book. The panel on the right shows the overlap test run against every booking already in that room.
▸ Book 10–11, then 11–12 — then flip the ≤ chip and try again.