Teach circuits that actually run, free for 30 days.

Open the circuit the class is going to work on, hold the parts and the wiring, and hand it to the class from the class page. Every student gets their own copy with the same things held.

A held part cannot be moved, rotated, deleted, rewired or retyped by anybody the work was set for. Adding parts, wiring into a held pin and running it are untouched, because that is what they are there to do. Forking the copy does not release it: the copy is theirs, the lock is yours.

The class page has a Wall tab: one card a student, with the circuit they have open drawn on it. It is the diagram itself, at rest, redrawn as they save, so nothing on it can be out of date.

It asks every fifteen seconds while you are looking at it, and a card whose circuit has not moved comes back without one. A student who has saved nothing for ten minutes gets the word "stuck?" beside the time. A question, because a student who is thinking looks exactly like a student who is stuck.

In a room, press somebody’s face and your canvas eases on to their view: their corner of the board, at their zoom, with their pointer showing as a soft ring. A frame in their color and a pill say whose view you are on.

Pan, zoom or touch the canvas and it is yours again, with the pill saying why. Going the other way, Bring everyone here puts thirty screens on your view in one press, and anybody can stop it the same way.

Pick 1, 2, 5, 10 or 15 minutes, or type a number, and everybody in the room reads the same clock. The room holds the moment it ends, not a count each machine keeps, so a laptop that slept and somebody who joined halfway through still reach zero together. At zero it flashes once and holds 0:00 until you clear it.

Everybody but you has a Hand up button, and the hands are kept in the order they went up. Your bar reads how many are up and whose, you press a mark to take one down, and Lower all clears the queue between questions.

Each student works on a copy of your circuit, so the useful question is what the student did to it. Under every project assignment the class page lists one line per student: parts and wires added, removed and moved, properties changed, notes written, and the sketch line by line. You can scan a whole class without opening each project.

Changes opens the rest, with the differences drawn on their own board: added things glow, deleted things sit dashed where yours had them, and a part that was dragged has an arrow from where it started. What you held is left out of the count, because a lock is how the work was set, not work the student did.

Under an assignment, Checks: a short list of things you expect the circuit to do, each one a sentence you fill the gaps in. Pin 13 blinks every 1000 ms, within 50. The serial monitor prints a line matching this. Press this button, then that pin goes high. The sketch builds.

Try it on the starter runs the list against your own answer before the class ever sees it, so a check that does not pass on the solution never gets assigned. Then every student gets Check my work, which runs the same list on the real engine in their own browser and tells them what it measured beside what you asked for: it toggled every 1462 ms, expected every 1000. The score comes back on the wall and on the submission, a failed check drops into your comment in one press, and Mark it re-runs them all on your machine when the marks have to be yours rather than theirs.

Next to Changes on every submission, Send feedback opens a box: write a line, save it, and it is on the student’s own class page the moment they next open it. Use it for what to try next, what stood out, or a nudge toward the part they left off.

Editing replaces what was there rather than piling comments up, so a submission carries one note, always the newest. It is signed as you, and the same class rules that hold a starter say who else may write it: nobody but the teacher.