Magic Squares of Order 4
(requires JavaScript)
A mouseclick on any number of the greenbordered square ("numberpool") moves this number into the first empty
field of the redbordered square ("magic area");
a click on any number of the magic area brings the number back to its original place in the pool.
Aim: 
A magic square of size 4 x 4 is to be constructed, depending on choice a general, a panmagic or a symmetric one. 
When "show" or "quick" is activated, a backtracking algorithm will continue the search for a solution; interruption can be caused
by clicking the option "mouse". If the Stopoption is activated, the algorithm will stop, whenever a solution is found, and in that case, a search for a next solution may be continued with the corresponding button. The blue bordered square always displays the last found solution. The delay (in milliseconds) regulates the frequency of image output, if "show" is activated.
