<html> <head> <style>.dark, .light{width: 100px; height: 100px; border: none;}.dark{background-color: black;}.light{background-color: lightgray;}</style> </head> <body> <h2>Checkers Pattern</h2> <button class="dark"></button> <button class="light"></button> <br><button class="light"></button> <button class="dark"></button> </body></html>]]>