﴿ قَالَ بَلْ أَلْقُوا۟ ۖ فَإِذَا حِبَالُهُمْ وَعِصِيُّهُمْ يُخَيَّلُ إِلَيْهِ مِن سِحْرِهِمْ أَنَّهَا تَسْعَىٰ ﴾

“He answered: "Nay, you throw [first]." And lo! by virtue of their sorcery, their [magic] ropes and staffs seemed to him to be moving rapidly:”

He said ‘Nay you cast!’ and so they cast and lo! their ropes and their staffs ‘isiyyihim derives from ‘isūwwun but the two wāw letters have been changed into two yā’ letters with the kasra vowelling applied to both the ‘ayn and the sād appeared to him by the effect of their sorcery as though they were snakes gliding swiftly on their bellies.