For more detail this asset from the Unity Asset Store: Click Here
This is a paid asset, but now you can download Contrast – Tunnel Survival for FREE, Please keep in mind this package is provided only for learning purposes or to be able to test before buying the product, NOT FOR COMMERCIAL PURPOSES.
Contrast – Tunnel Survival v1.0
“If possible, please buy the package to support the developer”
Contrast is a complete arcade game template which is ready to release.Features: * Complete, ready to release project. * World curvature vertex shader included. * Extensively commented, clear C# code. * Optimised for mobile and standalone. * Touch and keyboard input. * Infinite, procedural levels. * Easy to modify with full instructions.
For those who want to dig a little deeper there is documentation guiding you through the creation of your own tunnel variations.