54Going back
A lesson is not only where it ended up. The question as it was first written, the attempt that went wrong, the moment it clicked — all of that is worth keeping, and Slate does. The time machine slides back through this board, and milestones and snapshots keep the points you want to hold on to.
Find itTools → Time machine, beside Region — the other panel that opens over the board. It walks the board in the order the lesson was made, the same order the player and a region use — so a detached diagram steps through box, arrow, box rather than through every arrow first.
Slide back and lookDrag the slider and the board shows itself as it was. It is a preview: the board is outlined in amber and a banner says Preview — not the live board, because nothing you are looking at has changed anything. Now brings you back. The slider runs over every mark on the board, in the order you made them — step 0 is an empty board, step 40 is the first forty marks — so a lesson with two hundred marks has two hundred steps. There is no ceiling on it and nothing is stored to provide it: the board itself is the record, which is the same order the replay plays in.
What the slider does not showIt walks the marks that are on the board. A mark you moved or recoloured later appears in its final state rather than its first, and a mark you deleted is not on the timeline at all. Undo still covers the last few of those (ten, or five on Battery saver), and a snapshot covers anything you want kept for good.
Replay from a pointReplay hands that point to the player and plays the board building itself up to there — the same replay as everywhere else, with beats, speed and the rest. Esc brings the board back exactly as it was, preview or not.
MilestonesMilestone names the point you are looking at and keeps it. The name box offers the ones a lesson actually uses in order — Question, First attempt, Key insight, Correction, Final solution — so naming one is usually a tap and Enter. Milestones are listed in the panel, can be renamed or removed, and stay with the board when you save it.
SnapshotsSnapshot keeps the same thing with a picture of itself, so the panel shows you what each one is rather than only what it is called. Each snapshot carries its name, its thumbnail and the time it was taken. Tap one in the panel for everything you can do with it.
What a snapshot actually isNot a screenshot. A snapshot holds the real marks — every stroke, shape, note and picture as its own object, written the same way the board itself is saved. That is what makes the rest of this chapter possible: you cannot fork, restore, copy from or edit a screenshot. The thumbnail is only its face.
ForkFork makes a new board from that point and leaves the one you are on completely alone. The new board arrives named after where it came from, with its own history and its own beats — so you can take the lesson a second way without losing the first. Useful for “here is what happens if we try it like this instead”.
RestoreRestore puts this board back to that point. Before it changes anything it keeps what is on the board now as a snapshot called Before restore, with the time — so work is never quietly lost, and one Undo also steps it back. Restoring to an earlier point removes the marks made after it, which is what restoring means. Restore is the only button here marked in red, because it is the only one that changes the board you are on.
Copy from a snapshot or milestoneCopy onto this board brings that point’s marks onto the board you are working on without replacing anything — they arrive slightly offset and already selected, ready to drag into place. This is the one to reach for when you want the original question back on the board under the working, a diagram you drew earlier reused rather than redrawn, or a finished example brought into a new explanation.
Put a snapshot on the boardPlace it on the board drops a snapshot object onto the board: a small picture of that point that you can move, resize, rotate, crop, duplicate and delete like any other picture, and open in the image lab. It is more than a picture though — right-click it for Open as a new board, Copy its contents onto this board, Restore the board to it, Export it and Rename, because it is still carrying the work inside it. Put three of them along the bottom of a board and you have a visible before-and-after of a whole lesson.
Export one on its ownExport as a picture saves just that milestone or snapshot, rendered at full board quality through the same export Slate uses everywhere — surface, frame and all — not the little thumbnail. Handy for a worksheet showing the question and the answer side by side.
What travels, and what does notMilestones and snapshots are saved in your .slate file and come back when you reopen it, with their marks intact and editable — and because the slider is built from the board itself, the whole timeline comes back with the file too. A board may keep up to thirty milestones and snapshots — they hold real work, so they have real size. Files saved before this existed simply have none, and open exactly as they always did.
In a nutshellPreview to look, Replay to watch, Milestone or Snapshot to keep, Fork to branch, Restore to go back, Copy to bring a piece of it forward.
Part of the Slate guide — or read the whole guide on one page.