Answer:
This is the design I was looking at.
Explanation:
Your question is a bit confusing because I'm not sure where the sentence I'm meant to rewrite starts from but I'll assume (I hope correctly) that the sentence is "this is the design I was looking"
In that case, when rewriting a sentence to include prepositions were required and removing the unnecessary ones, my best revision of the answer is in the "Answer" column.
A preposition is a word which precedes a noun or pronoun to show relationship between another word in the same sentence.
Some examples of preposition are: after, for, in, at, etc.