Good eyes...the towers are from Warbases modular (I had doubts about building sturdy tall structures). I ended up doing a small test order with Warbases (still have an unbuilt stable on the plan) and the blank modulars seem like a great product. I just kept making things with the materials I had on hand and never got around to another order. I should have just ordered a bunch and saved myself some time as I ended up using the same widths, heights so it would work with the towers.