The Black Line leads you to Mr.Fuego.
The Blue Squares are the trainers that will battle you if they see you.
Thee Light Green Squares are the Items you can pick up.
The Purple Square is Mr.Fuego.
The list below shows some items you can find in Fuego Iron Works
TM 35 Flamethrower
For every Star Piece you give him, you get one of every kind of shard, Green, Red, Blue, and Yellow. This is helpful if you want to learn some moves from the Move Tutors.