Write a program that allows the user to specify a circle with two mouse presses, the first one on the center and the second on a point on the periphery. Hint: In the mouse press handler, you must keep track of whether you already received the center point in a previous mouse press.

Write a program that allows the user to specify a triangle with three mouse presses. After the first mouse press, draw a small dot. After the second mouse press, draw a line joining the first two points. After the third mouse press, draw the entire triangle. The fourth mouse press erases the old triangle and starts a new one.

Implement a program that allows two players to play tic-tac-toe. Draw the game grid and an indication of whose turn it is (X or O). Upon the next click, check that the mouse click falls into an empty location, fill the location with the mark of the current player, and give the other player a turn. If the game is won, indi- cate the winner. Also supply a button for starting over