Take a look at these two done by a couple of our members. It may look like it was sewn both up and down and sideways but it isn't. In order for it to go together the width and height of each little square in a column need to be the same. Let your eye follow the pattern up and down to see what I mean.
There are several how to videos on u=tube you should watch. HTH I haven't started one yet but have been researching.
http://www.quiltingboard.com/pictures-f5/diamonds-jubilee-bargello-t196199.html
http://www.quiltingboard.com/picture...o-t207648.html