objective of this puzzle is to place all pentominos on the board
after you have marked four squares to remain empty.
clear the board you push the button that says "begin".
A grid will appear. In the grid click on four different squares.
They will turn black. Then click on the pentomino of your choice,
hold the mouse-button and drag it on the board.
remove a pentomino you can drag it over the edge - any edge - of
the board and release it. Push (or hold) the right mouse-button
to rotate; double-click to flip the pentomino.
an excellent exercise in visual spatial relationships and memory.
Once you have accomplished it with the black squares in one place,
then move the black square around and try again. This puzzle exercises
the right brain very effectively.