A man who lived in the desert asked the Messenger of Allah ﷺ about the prayer at night. He made a sign with his two fingers-in this way in pairs. The witr consists of one rak'ah towards the end in night. (Using translation from Abū Dāʾūd 1421)
أَنَّ رَجُلًا سَأَلَ رَسُولَ اللهِ ﷺ عَنْ صَلَاةِ اللَّيْلِ فَقَالَ «مَثْنَى مَثْنَى وَالْوَتْرُ رَكْعَةٌ مِنْ آخِرِ اللَّيْلِ»