I was hoping for a more musical explanation...but I'l go with this. Thanks for explaining that everyones! /bowsSKULL_KRUSHER is right. Each post-tensioning bar is 3 inches in diameter. High strength grout will be pumped from the lower location until it starts weeping out through the top location several floors above. Then you know the bars are fully sealed with grout. The bumps that you see in the silver sheathing is where the coupler that joins two bars is located. Just a trivia: This is the 3rd high-rise structure (including CN Tower) in Canada to have post-tensioned walls.