Reference for Eruvin 153:8
משום דהוה לזה תשמישו בנחת ולזה תשמישו בקשה וכל לזה בנחת ולזה בקשה נותנין אותו לזה שתשמישו בנחת
R'Nahman ruled: A wall between two courtyards, one of whose sides was ten handbreadths high<span class="x" onmousemove="('comment',' Above the floor level of the courtyard adjacent to it.');"><sup>20</sup></span> and the other one of which was on a level with the ground,<span class="x" onmousemove="('comment',' Of the other courtyard whose floor was on a higher level than that of the former, and was within tell handbreadths from the top of the wall. By 'level with the ground' a height of less than ten handbreadths is to be understood.');"><sup>21</sup></span> is assigned to that courtyard with the floor of which it is level,<span class="x" onmousemove="('comment',' Sc. only the tenants of that courtyard are allowed to carry their objects up to, and down from, the top of the wall. To the tenants of the other courtyard this is forbidden.');"><sup>22</sup></span>