Many Ways to "Crawl"
Prior to having children, I assumed that all babies crawled on their hands and knees in relatively the same manner around the same time. After watching Danny, Sean, Evan and Logan, I know this is not true.
Danny did the army crawl, Lt. Dan style
Sean rolled where he wanted to go
Evan got around on all fours (look at how chunky he was!)
And this is Logan's method of transportation...the reach, scooch and pull through
It may not seem it from this video but he can actually get around quite quickly if he wants to.