How can I wrap tubes exceeding my theoretical cube back around to the other side in a periodic fashion?

I am simulating a cube of random size, say 100X100X100 mm. I then insert tubes into this cube. I then want to write a code to plot a smaller cube than the one made above and wrap tubes exceeding the boundary of this new smaller cube back around to the other side in a periodic fashion. For example, if a tube was exceeding the boundary on the right side of the cube, the exceeding portion would get cut off and placed on the left hand side within the boundary, as if the cube is part of a much larger network of cubes. Any tips or advice would be welcome!