Tower building challenge
Charcoal, 48 bytes

ＦＮ«Ｍ×Ｘ±¹ιＩ§224ι←Ｂ⁹±⁶*↗↗↑↓²→⁵↖↑²←⁵↖»ＧＨ&lt;⁵*Ｍ⁷←ＧＨ&lt;⁴*


Try it online! Link is to verbose version of code. Explanation:

ＦＮ«


Draw N Blox.

Ｍ×Ｘ±¹ιＩ§224ι←


Adjust the horizontal position before drawing each Blox.

Ｂ⁹±⁶*


Draw the outer wall of the Blox.

↗↗↑↓²→⁵↖↑²←⁵↖»


Draw the inner wall of the Blox.

ＧＨ&lt;⁵*Ｍ⁷←ＧＨ&lt;⁴*


Raise the roof.