There appears to be an error on this page:
Near the middle bottom of the page we find these lines:
Rectangle house (300, 120, 200, 170);
g.fillCheckerBoard (house, 30, 10, Colours::sandybrown, Colours::saddlebrown);
However, the API for fillCheckerBoard found here:
Lists fillCheckerBoard as taking a Rectangle <Float>, I can verify that my code would not run using Rectangle<Int>. So I’m not 100% if the bug is with the example or API, but there is a discrepancy.