We used to be able to use the /execute detect command in a chain like this:
/execute @a ~ ~ ~ detect ~ ~-1 ~ stone 0 detect ~ ~-2 ~ stone 0 say I've got 2 stones under me yay
It worked as far as I remember and was used to test for multiblock structures.
Seems to be broken now... please try to replicate. Fix appreciated.
Maybe you've meant
but not sure if execute can exceute another execute command
An execute commad can have only one detect clause.