Ever wanted to be an agent
of the U.S. Treasury? Well, here's your chance.
The Treasury would like to replace the old Eisenhower silver
dollars in circulation with the new Sacagawea gold dollars.
Your goal is to turn all the coins on the board into gold
dollars by a sequence of mouse
When you click on a silver dollar, it changes to a gold one;
when you click on a gold dollar, it changes to a silver one.
In addition, each click changes the make of the dollars of the
entire row and column that contain the dollar you've clicked.