Responsa for Eruvin 176:3

מאי בינייהו אמר אביי אריך וקטין איכא בינייהו

but in one that is less than four cubits they cannot be absorbed.<span class="x" onmousemove="('comment',' And, since the water inevitably flows into the public domain, his desire is fulfilled (cf. Supra n. 8 second clause) .');">⁶</span> What is the practical difference between them?<span class="x" onmousemove="('comment',' R. Zera's and Rabbah's explanations.');">⁷</span> - Abaye replied: The practical difference between them is a courtyard that was long and narrow.<span class="x" onmousemove="('comment',' Eight cubits by two, for instance. According to R. Zera's explanation it is permitted to pour water into it, since an area of 8 X 2 = 4 X 4, and the water would be absorbed in the courtyard itself before any of it reached the public domain. According to Rabbah, however, this is forbidden, since a narrow courtyard is an unsuitable place for spraying.');">⁸</span>

Teshuvot Maharam