Sorry if it is a little long. I try to work as non destructive as possible, but the last part needs some manual edits to get the distorted triangle effect.
Half a circle (75 px)filled with a dark global color is rotated from the lower right corner with a Transform effect: 35 copies, angle -10°. To get clean filled objects, a Pathfinder effect Exclude was applied and moved to the bottom of the Appearance panel stack. This only works when the Stroke is hidden.
A second Transform Effect is applied, 1 copy is reflected along the X axis.
The result is grouped and a new fill with a light global color is added and dragged below the Contents item in the Appearance panel. The fill is converted to a circle with the Convert to Shape > Ellipse effect. An Absolute size is specified to match the size of the object. A final Pathfinder > Divide Effect is applied as the last item in the Appearance Panel.
I saved the project under a different name because the next steps are destructive. Use Object > Expand Appearance and Object> Ungroup to get separate individually editable shapes.
Remove the objects to get a single dark colored and a single light colored column. I made them into 2 colored groups.
This is the boring part, you need to split every object in two and give it different colors. You can make it faster by recording 2 actions. This is where global colors are useful. Zoom in and Double click the dark colored group to get into Isolation mode. Direct Select only the bottom part of a shape (drag over the 2 lower sides). Cut them. Paste in Front. Join. Fill
Repeat to create the other triangles.
The 2 triangle groups are transformed separately. The vertical one is transformed from the bottom center. The rotated one is transformed from the bottom right. Both are transformed 10°.
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