Triangular Domino Prism
Java Applet Instructions

The Green Flag resets the puzzle.

Pressing the Spacebar scrambles the puzzle.

Down Arrow turns the bottom eight cubelets by 180 degrees. The
same can be achieved by clicking on the top of the front center trangle.

Right Arrow turns the right eight cubelets by 180 degrees.
The same can be achieved by clicking on the top of the right center triangle.

Left Arrow turns the left eight cubelets by 180 degrees. The
same can be achieved by clicking on the top of the left center triangle.

To turn one of the three corner columns by 180 degrees, click on the top
corner triangle of the upper cubelet.

Pressing a turns the top layer by 120 degrees clockwise.
The same can be achieved by clicking on the leftmost face of this layer.

Pressing y or z turns the top layer by 120 degrees
counterclockwise. The same can be achieved by clicking on the
rightmost face of this layer.

Pressing s turns the bottom layer by 120 degrees clockwise.
The same can be achieved by clicking on the leftmost face of this layer.

Pressing x turns the bootom layer by 120 degrees counterclockwise.
The same can be achieved by clicking on the rightmost face of this layer.

Klicking on the top of one of the central edge triangles turns
the entire edge by 180 degrees.

Pressing q flips the entire prism over by 180 degrees
in the direction back > right.

To solve the prism, you have to get the top side yellow,
the left side blue and the right side red. (The green back and the white
bottom are invisible.) When you solve it, your time taken is displayed
for 5 seconds.
Notation

There are two layers, the upper layer and the bottom layer.

In each layer there are three corner cubelets (front  right  left),
three edge cubelets (left  right  back), and three central cubelets
(front  right  left).

U means turning the top layer by 120 degrees clockwise
(when viewed from above)

U' means turning the top layer by 120 degrees counterclockwise
(when viewed from above)

D means turning the bottom layer by 120 degrees clockwise
(when viewed from above)

D' means turning the bottom layer by 120 degrees counterclockwise
(when viewed from above)

F means turning the part of the prism consisting of the
front eight cubelets by 180 degrees

R means turning the part of the prism consisting of the
rightmost eight cubelets by 180 degrees

L means turning the part of the prism consisting of the
leftmost eight cubelets by 180 degrees

f means turning the front column of the prism consisting of
two cubelets by 180 degrees

r means turning the rightmost column of the prism consisting of
two cubelets by 180 degrees

l means turning the leftmost column of the prism consisting of
two cubelets by 180 degrees
Solution Strategy

The very first step is to get the top three inner triangles yellow.
By turning them, check which inner triangles have triangles of the
same colour underneath. Turn the layers and invert the inner
trangles until all pairs are of opposite colour (yellow  white).
Then make the top three triangles yellow by turning again
with the arrow keys (or by clicking on the top inner triangles).

Next we want to get the three corner columns right.
This can be done intuitively
by moving the two pieces into their respective positions. For instance,
start by solving the left column: greenyellowblue on top,
bluewhitegreen at the bottom.

Now get one of the remaining four corner pieces into its
correct position. For instance, let us assume that the bottom top
piece (yellowredblue) is correct. Then the third top corner
(the right one) is either in the correct (right) column or the bottom
front piece. In the latter case, use D'  R  D to get it
where it belongs.

Finally, the only possibly incorrect corner pieces can be the ones
at front bottom and right bottom. To interchange them, use
R  U  F  U'  R. Then the three corner columns should be
correct.

From here on, we can follow the strategy for the
Triangular Pocket Prism by considering
the corner columns and the adjacent inner
triangles as one column consisting of two
quadrangular pieces.

Interesting things can happen here. For instance,
exactly one vertical pair of inner triangles can be interchanged.
For possible rotations of the inner triangles, check out the
Triangular Super Domino Prism.

Any useful algorithms and shortcuts are welcome. Please tell me
about your discoveries!