Reference for Shabbat 200:1
לאו היינו מתני' וא"ר יוחנן והוא שנח ע"ג משהו א"ל מתגלגל קאמרת מתגלגל אין סופו לנוח אבל האי כיון דסופו לנוח אע"ג דלא נח כמאן דנח דמי קמ"ל:
Is this not [to be deduced from] our Mishnah, whereon R. Johanan commented. Providing it rests on something, whatever its size?<span class="x" onmousemove="('comment',' Since he does not explain that the object came within three, it follows that even then it must alight on something. ');"><sup>1</sup></span> You speak of [a] rolling [object]. replied he; [a] rolling [object] is not destined to rest; but this, since it is destined to rest,<span class="x" onmousemove="('comment',' It is actually falling when intercepted within three handbreadths from the ground. ');"><sup>2</sup></span> [I might argue that] though it did not come to rest, it is as though it had rested:<span class="x" onmousemove="('comment',' Hence the thrower is culpable. ');"><sup>3</sup></span>