FrameMensa Quiz #1 -- Paragraph Spacing

This sounds easy:

Work out how to format a document that comprises two kinds of
paragraphs, so that ordinary body text and headings align with grid
lines spaced vertically, four to the inch. 

Each body line is to take a quarter of an inch of vertical space.
Consecutive paragraphs are to be separated by a single blank line.

Each heading line is to take two lines' worth of space, with the heading
text in the middle of that space -- that is, the headings are displaced
half a line from the rest of the text, spaced with a quarter line above
and a quarter line below. 

It's not a trick question -- at least, I don't think it is.

Hint: 

If you put a 0.125 inch Space Before a normal paragraph, and 0.125 inch
Space After, Frame overlaps these spaces and the paragraphs are
separated by 0.125 inches, not 0.250. 

If you put 0.250 inches either Before or After a normal paragraph then
you will get the desired space between normal paragraphs, but an
intervening Heading paragraph then has to contend with a minimum of
0.250 inches of space above or below. An additional complexity is that
Frame disregards Space Below a paragraph that falls at the top of a
column. The formatting has to continue to function in this case. 

Use of baseline synchronization is prohibited. But you can use Frame
Above and Frame Below if you have to.

C.