I used the div elements to create a block container to hold the inline block divs that create the black squares. I gave each of the div elements a left and right margin of 2px to give some space between the elements.
[Challenge 1] (http://codepen.io/tbrandle/pen/yVKbzg)
I used 3 section elements to contain the divs. I created a class for each of the divs to float position the divs. I used float element to position the divs.
[Challenge 2] (http://codepen.io/tbrandle/pen/XNERyE)