Right, it is clearer to me now. When I logged in and clicked on this subject it must have come up on page 2. There was no trace of an earlier page, although, not expecting this, I didn't check page numbers. I first came to bogstandard's contribution and talk of cylindrical squares, so I checked the calendar to see if it was April 1st.
Using squared-off pipe stubs, perhaps in pairs at times, is a good idea that I must follow up.