Difference between “Complete binary tree”, “strict binary tree”,”full binary Tree”?

Perfect Tree:

       x
     /   \
    /     \
   x       x
  / \     / \
 x   x   x   x
/ \ / \ / \ / \
x x x x x x x x

Complete Tree:

       x
     /   \
    /     \
   x       x
  / \     / \
 x   x   x   x
/ \ /
x x x

Strict/Full Tree:

       x
     /   \
    /     \
   x       x
  / \ 
 x   x 
    / \
    x x