The Zone Trio

Now it's been said in the past that Wood Zone and Metropolis Zone are Linked. Why do people think this?
1: Tree Trunks look like Metropolis accelerators, and the colours of both are Green and Brown.

2: Both levels have the same music in Beta Sonic 2 and in the Final with Wood Zone palette.

But is this correct? Also, Craig Stitt mentioned how Metropolis had been redone several times. Probably because the other level artist was trying to keep up with the changes Brenda Ross (Wood Zone's level artist) was making! Also Craig Stitt mentioned how Time Travel was considered for Sonic 2.
"According to the interviews SEGA employees were forced to gi...so kindly had time to give, they got the instructions to create a forest that would later burn down and become a metalic fortress. Makes sense - look at the hollow tree trunks and compare them to Metropolis' warp tubes. " - Area 51

Now onto the third zone. Mushroom Hill. Yes thats right, well it's not neccesarily correct, but you never know :)
Why do I think this:
1: Mushroom hill is very Nature based, as in trees in the background etc.

2: This made my heart jump when I thought of it. Sonic 3 Level select icon for Mushroom "Valley" is Metropolis!


And yes, Metropolis and Wood Zone are definatly separate zones.

Personally this fits with the Sonic Team "Apology".
They put in the zones they took out in the earlier games. And Mushroom Valley/Hill is the new implementation of Wood Zone.

Also on a sidenote, the Sonic Adventure zone "Windy Hill" is named "Windy Valley" in the OST CD. Maybe it's yet another SEGA joke?!