These div's have a fixed width of 20em. As the window gets narrower, the rightmost div ought spill onto the next line.

These div's have a fixed width of 20em. As the window gets narrower, the rightmost div ought spill onto the next line.

These div's have a fixed width of 20em. As the window gets narrower, the rightmost div ought spill onto the next line.

These div's have a fixed width of 20em. As the window gets narrower, the rightmost div ought spill onto the next line.

These div's have a fixed width of 20em. As the window gets narrower, the rightmost div ought spill onto the next line.

These div's have a percentage width of 25%. As the window gets narrower, the rightmost div ought spill onto the next line.

These div's have a percentage width of 25%. As the window gets narrower, the rightmost div ought spill onto the next line.

These div's have a percentage width of 25%. As the window gets narrower, the rightmost div ought spill onto the next line.

These div's have a percentage width of 25%. As the window gets narrower, the rightmost div ought spill onto the next line.

These div's have a percentage width of 25%. As the window gets narrower, the rightmost div ought spill onto the next line.