In the sequence $($A$),$ on the left, the robot lifts an individual foot

at a time alternating between feet $1,3,2,$ and $4.$ In the gait

sequence $($B$),$ on the right, the robot alternates between

simultaneously lifting feet $1$ and $3,$ and feet $2$ and $4.$

Using the notational conventions covered during the course for

describing footfall sequences enter the corresponding footfall

sequences for each of the above examples.

What type of stability is exhibited for each of the footfall

sequences?