Split your lesson into parts. The board shows what the class is doing now, how long is left, and what comes after. A train runs along the line and stops at a station as each part ends.
Your lesson
Quick add:
Ready-made plans
Options
Saved for offline use. It will work without internet next time.
Teacher tips and shortcuts
Space pauses and carries on. → moves on to the next part now, ← goes back to the start of the last one. + and − add or take off a minute from this part only. F is full screen, M turns sound off, Esc opens this menu.
The strip along the bottom is the whole lesson. Ticked parts are done, the white one is now, and the time under each part is when it ends by the clock.
Your plan is kept in this browser, so it's there next time.
The timer goes by the computer's clock, so it stays right on a slow laptop or if you switch to another tab.