If Simon flashes red in the upper left square and blue in the lower right square, put your mouse over the upper left square, choose red (see below) and click, then over the lower right square and choose blue and click.
Simon will start out with two colors in two different squares, spaced about 1 second apart and eventually evolve over the course of the game to 9 color flashes of red, green, blue, and yellow, spaced about 7/10 second apart. It will change from two squares to three squares at a score of 8 and three squares to four squares at a score of 20, and so on.
Click start and it is your turn whenever the bell rings. When you get it right it beeps and starts the next round of flashes. If you are wrong it buzzes and your error is shown at the bottom..
The squares are numbered 0 to 9. The first row is 0-1-2, the second row 3-4-5, and the third row 6-7-8. If Simon, "Me", as shown in the figure, shows "3b6r5g6y" then in the last round, the one you failed on, Simon flashed blue in the first square in the second row, then red in the first square of the third row, then green in the last square of the second row and then yellow in the first square of the third row. The player's response is below that and he or she chose the wrong color for the third flash.
You can "practice" in the square below to see if your mouse will work with the game before downloading it. Place your mouse over the square and try scrolling up and down, then left and right. Note how the numbers change as you do these maneuvers. Unfortunately what happens depends on the browser you are using and the platform you are on, Mac, pc, ...
In the actual application, Simon9by4, scrolling up is red. Down is blue. Left is yellow. Right is green. Note with a mouse with a wheel you may have to click the wheel (Kensigton) to switch from vertical scrolling to horizontal scrolling . The standard Apple mouse with the scroll ball and he Apple magic mouse or trackpad require no special alteration.
Note that, if the square were a web page, scrolling "up" would move the web page down.