"On the morning of Al-Aqabah, while he was on his mount, the Messenger of Allh said: 'Pick up (some pebbles) for me.' So P picked up some pebbles for him that were the size of date stones of fingertips, and placed them in his hand. He started to do this with his hand." Yahya described him shaking them in his hand like this. (Using translation from Nasāʾī 3059)  

قَالَ رَسُولُ اللهِ ﷺ غَدَاةَ الْعَقَبَةِ وَهُوَ وَاقِفٌ عَلَى رَاحِلَتِهِ «هَاتِ الْقُطْ لِي» فَلَقَطْتُ لَهُ حَصَيَاتٍ مِنْ حَصَى الْخَذْفِ فَوَضَعْتُهُنَّ فِي يَدِهِ فَجَعَلَ يَقُولُ بِهِنَّ فِي يَدِهِ وَصَفَ يَحْيَى تَحْرِيكَهُنَّ فِي يَدِهِ بِأَمْثَالِ هَؤُلَاءِ