According to the laws of carrying on shabbos one may not carry from one domain to another aside from a makom petur ("exempt area"). A makom petur is less that 4X4 handbreadths and more than three handbreadths off the ground (source).
Say you have 2-3 steps attached to your house, which domain category is each step in? Does the higher step's height begin from the step below it or does it go to the very bottom? Also does each step going upwards inherit the width of the steps below?
If either or all steps are makom petur then does that mean that you can carry inside from the step?
Let's assume that we're talking about standard steps. About half a foot long, half a foot high and 4-5 feet wide. Let's also assume that a tefach is between 3 and 4 inches.