Click the sim once to enable it to respond to keyboard keys.
Click for playback controls and for sim info and reset.
Only two tile pictures are used (light and dark).
Tile numbers are local character variables added
in the paint window.
Pressing the space bar anytime will shuffle the
pieces. The shuffle ring moves at random, in a similar
fashion to a 'ladybug', ie it cannot move backward
and so unshuffle the previous move.
The shuffle ring counts down each move to zero
and then heads for the lower right corner before
Tiles in the correct position light up and their
number changes from grey to red.
A bit of maths determines if a tile should appear
lit. The calculation is:
Tile No = 4*(4-V) + H
where V = vertical position of tile
and H = horizontal position of tile
(remember lower left position is 1,1).
Any piece in the same row or column as the space
can be clicked, allowing several pieces to be moved
at once, as in the real puzzle.
The background turns orange when the puzzle is
correctly completed, -but only after at least one
shuffle has been done.