Lego is interchangeable it can be used as a noun or adjective.
"LEGO is a massive corporation" - noun
"Put away the lego, timmy" - noun
"Mom, can I buy a box of lego" - noun
"That's a great Lego house" - adjective
"That's a Lego car" - adjective
Fast is an adjective only due to being a describing word. Tho this can change if for instance a person place thing or idea were named "Fast" it would then become a noun.
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u/trappedinabasemant Jul 30 '24
Calls Lego an adjective.
Starts sentence by using Lego as a noun.