Do you ever spend six months working on a quilt project only to find that one of your basic assumptions was wrong?
I started my hexagon quilt last November and since I tend to plan everything out in Excel I used the grid to work out how many hexagons I would need. I know that when you are calculating how many blocks are in a given top the formula is the same as the one for square blocks on point — that is, xy + (x-1)(y-1). Unfortunately, calculating how many rings you need to make for a top is NOT the same for hexagons as it is for squares or diamonds. Surprisingly enough, the first ring is 6 blocks, not 4, and it goes up by 6 for each ring. Also you can’t fit as many hexagon rings into a top of a given size as you can square blocks.
In my previous calculations I believed that I would need 14 “rings”, plus the centre block, giving me a total of 365 blocks. However, I recently found some hexagon grids online and plotted the layout using the correct grid, and the result is very, very different. If I stick to the plan of applying each flower to a 3″ hexagon (finished size 6″ point to point, 5.25″ side to side), then I have two options, both of which give me a quilt top measuring roughly 75″ x 85″. [NB: each hexagon here represents the background square — the colours are just to help visualise the larger structure.]

The first option has each hexagon flower arranged vertically (points at north and south) with the rings oriented horizontally. This would require 257 blocks in 6 complete rings with partial rings in the corners, and the top size would be roughly 74″ x 87″.

The second option has the hexagon flowers arranged horizontally (points at east and west) with the rings oriented vertically. This option has 281 blocks in 8 complete rings with partial rings in the corners, and the top would be roughly 78″ x 89″.
Both options 1 and 2 could be made either as a complete top to be quilted, or as a “bind as you go” project (subject to finding backing fabrics that aren’t too jarring).

There is, however, a third option. If I attach a grey hexagon at each V in the flower, I get a “virtual” hexagon measuring 3″ on a side — the same as the appliqué block. I would need the same 281 flowers as for Option 2 but only a small fraction of the background fabrics. Placement of grey hexagons for the larger rings would require attention to detail so as not to get the fabrics in the wrong position, but it’s doable. It would mean a lot more hand sewing but that’s not a disincentive *g*.
Hmm … decision, decisions.
At the rate I’m sewing (wrists permitting) I should achieve 281 hexagon flowers by the end of July. That gives me nearly two months to think things over.