Whenever Messenger of Allah ﷺ came out on ʿId day, he used to order that a Harba [??] (a short spear) to be planted in front of him (as a Sutra for his prayer) and then he used to pray facing it with the people behind him and used to do the same while on a journey. After the Prophet ﷺ , this practice was adopted by the Muslim rulers (who followed his traditions).
أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ إِذَا خَرَجَ يَوْمَ الْعِيدِ أَمَرَ بِالْحَرْبَةِ فَتُوضَعُ بَيْنَ يَدَيْهِ فَيُصَلِّي إِلَيْهَا وَالنَّاسُ وَرَاءَهُ وَكَانَ يَفْعَلُ ذَلِكَ فِي السَّفَرِ فَمِنْ ثَمَّ اتَّخَذَهَا الأُمَرَاءُ