This an exercise only. Considering the fact that life energy transmits thorough hyper paces a wall of life energy in three dimensional space is totally ineffective. However it is the concept of protection that the drawing of circles and the erection of walls signify. Based on this extended concept you are capable of expanding the effect of the sphere into serving as a protection. The actual protection becomes a sphere that extends into hyper space and that cuts off any life energy based transmission.
Most humans are incapable of actually visualizing hyper spaces.
However, use of the sphere or circle as a symbol gives sufficient protection in most cases. You may have heard of lots of methods of how to structure protective spheres. A skilled hyper space mathematician will penetrate any and all of these shields with no problem at all. However it is useful to begin somewhere. The circle of protection that you have set up just now is a good protection for the work with most energies.