The Gemara says that a board of 1.5 tefachim, space of 2, board of 1.5 and space of 10 will not work because the gaps of 2 and 10 on the sides of the 1.5 teach board will be mevatel. Why does lavud not work to fill the gap of the 2 boards turning it into a pas (5)? Thank you
Moshe Rubin, Brooklyn, ny
The Gemara, 5 lines from the top of 10b, asks why not make a board of 1.5 amah, a space of 2 amah, and then a board of 1.5 amah? The Gemara is not discussing 1.5 tefachim; it is discussing 1.5 amah. Since there are 6 tefachim in an amah, this means that we are discussing a board of 9 tefachim, a space of 12 tefachim and a board of 9 tefachim. Lavud works up to a maximum of 3 tefachim so it clearly cannot fill up the gap of 12 tefachim.
Kesivah vaChasimah Tovah
Dovid Bloom