Switching Fundamentals : Not Strong

R2 int f0/0.26 -> R7 int f1/1 (trunk)

R6 int e0/1 -> R8 int f1/6 (access)

R7 f1/13 --> R8 f1/13 (trunk)

One port on a R2 is a trunk to switch , other end the R6 port is access to the switch.
Yet it will work.
basic, but needed revisiting