Needed an extension on the back step from the house to the patio.

Did the cubic area calculations(twice) and looked in three internet tables for the number of bags(and size) of quick mix to fill the form for the extension.

Was about 1/2 bag short---and no time tom get another before the pour started to set---adding more after an hour(time necessary to get another bag)would create a cold joint---not a good thing with concrete.

So, wound up an inch low.

Turned the miscalculation into a design addition. Instead of a plain, gray addition, I used some on hand materials and four river pebble flooring squares to bring the addition up to the same plane as the old step.

The gray line that looks lower than the original step is grout and is actually even with the original step.

Funny part is our guard dog(Rottweiler/German Shepherd mix) will not touch the new area. The other two dogs do just fine.