parallel structure

[Solomon_13000]

An instructor uses a marker pen to write on the whiteboard while a chalk is used to write on the black board.

Is this sentence parallel structure? 'used' is in past tense.
Can anyone suggest a sentence that is parallel structure?

[Mordant]

Here are your fixes:

An instructor uses a marker to write on the whiteboard and chalk to write on the blackboard.

Markers are used on the whiteboard, while chalk is used on the blackboard.