Jeez. Took me a while. Couldn't figure it out. Got the right side to work, but couldn't get the 2 yellow frogs to get to the left. Never occurred to me to use justify content: center. Still trying to wrap my head around it (no pun intended).
I had a different solution that worked for me of
I was also having a hard time getting the 2 yellow frogs to line up in their lily pads! Finally got it after the help of this forum. Thanks!