Answer:
A trail, a union, together tied. Come across me and you will find you cannot change the course I'm on. Without me you cannot travel on. What am I?
I can be simple or I can be complex. I can be found in this riddle or in everyday life. I can be shapes or even colors.
There are four of us but it seems like everyone loves spades the most.
I am flora not fauna. I am foliage not trees. I am shrubbery not grass.
Sometimes I am white, sometimes I am dark. Most people love me. What am I?
Why did the teacher have to wear sunglasses?