Related for Niddah 51:53

והאיכא

Is there not in fact [the law that an enclosed space of] one handbreadth square and one handbreadth in height, forming a cube<span class="x" onmousemove="('comment',' Thus constituting a 'tent' of minimum size. ');">⁴⁹</span> conveys uncleanness<span class="x" onmousemove="('comment',' By overshadowing. If an unclean object and a clean one were overshadowed by it the latter becomes unclean even though it had not come in direct contact with the former. ');">⁵⁰</span> and constitutes a screen<span class="x" onmousemove="('comment',' Where the clean object was above, and the unclean one under such a 'tent'. ');">⁵¹</span> against uncleanness?<span class="x" onmousemove="('comment',' Oh. III, 7. ');">⁵²</span> — We spoke of the size of 'a handbreadth'; we did not speak of 'a handbreadth square'. But is there not the law concerning a stone that projected one handbreadth from an oven<span class="x" onmousemove="('comment',' So that it can be used as its handle. ');">⁵³</span> or three fingerbreadths from a double stove<span class="x" onmousemove="('comment',' Cf. prev. n. On the rendering of 'double stove' cf. Tosaf. 26b, s.v. [H], contra Rashi. ');">⁵⁴</span> in which case it serves as a connecting link?<span class="x" onmousemove="('comment',' Kel. V, 2. Between an object on the stone and the oven or stove. If the object was unclean its uncleanness is conveyed to the oven or stove and if one of the latter was unclean its uncleanness is conveyed to the object. ');">⁵⁵</span> We spoke only of cases where the size of less than a handbreadth is invalid, but here the law would apply all the more to such a case where the size is of less than a handbreadth and it is a handle of the oven. But is there not

Tosefta Rosh Hashanah (Lieberman)