what’s your meaning ?Seq logo?
Each pos. in logo stands for the pos of aligned promoter seq.
So this graph show the detail proportion of the each base in core promoter seq
the height of symbols within the stack indicates the relative frequency (relative proportion and conserved property) of each amino or nucleic acid at that position.
Check the Detail formula with paper ' Sequence Logos: A New Way to Display Consensus Sequences'--the original seq logos publication.