For your interpretation of the original sentence to be correct, there would have to be a comma after "16 feet" - i.e. "16 feet, taller than the east tower". Without the comma it means "16 feet taller than the east tower."

The grammar error, of course is "tallest". Because the comparison includes only two towers, you must use "taller", not "tallest".

HI, I wanted to understand that why do we assume that there are only two towers. The sentence doesnt gives out the total number of towers it just mentions two out of an unknown number of towers
Here is how i see that sentence.

Although the towers appear identical - Subordinate Clause
the west tower is the tallest - ( Main Clause saying that the West tower is the tallest of a group of towers)
standing 16 feet taller than the east tower - ( Noun modifier of noun West Tower which has been moved away from the west tower because it wanted to include a small predicate.)

Comment Please

Hi Plkt

The sentence mentions only two towers (east and west) so we cannot assume that there are more than 2 towers.

Also, a simple example to understand example

Tower A, B - Tower A is taller than tower B.
Tower A,B and C - Tower A is the tallest tower.