Because Isaac has very low tone in his arms, legs and trunk, he's never been able to crawl or get up on all fours by himself. Lately he's been doing this new thing where he gets up on his elbows, tries to lift his little bottom up and then starts to rock back and forth. You can see that this is very hard work for him. Maybe there is crawling in his future after all! Every milestone in life is HUGE! Neverever take mobility for granted.