Boards and buttons
Each card is one board, with its buttons in scan order: the main buttons,
then the bottom row. Use the arrows to reorder. More moves a button to the
other row, removes it, or customises it for this board only. Add a button
places another one. A new board can be opened by Switch press on the video
opens, by the When the video settings, or by an Open a board button on
another board. The Button library at the end changes a button everywhere
it appears.
How long the red screen stays up after "Take a rest" is chosen.
Alternating is predictable. Random stops the learner from learning the
sequence instead of reading the colour.
How long the grey screen stays up before the board asks again.