# Click on the image to give it focus, and then press any key.

# Note: The rectangle in this example may flicker as the operating
# system may register a long key press as a repetition of key
# presses.

draw <- function() {
    if (keyPressedVar == TRUE) {
        fill(0)
    } else {
        fill(255)
    }
    rect(25, 25, 50, 50)
}