The current design of the buttons 'swapping' with the previously selected activity could be drastically improved. It trades a single icon screen space for giving up the following features:

• Having muscle memory for where each activity icon is. This is why springboard (iOS launcher) is useful, because you remember where the app icon is, and you tap it, without having to look at it. Without static icon placement, it takes an extra 3-10 seconds at every interaction of the app to start an activity.

• Reminder visual indication of which activity is currently selected, by highlighting the current activity button like the tab bar does. Since the current design (which I appreciate with twins) shows the baby's name at the top bar, the only indication of what activity is the 'current' one is the visual layout of the controls in the center of the screen. Some of them look pretty similar (bottle vs breast feeding).

Both of these mean that I take much longer in the middle of the night stumbling around trying to start the right activity. Sacrificing one icon size screen area is a good tradeoff to get the above features back.