The slippers can aslo be worked using the following pattern for the sole and the top, as can be seen from the picture:

Row 1: ks, knit until last st, ks
Row 2: ks, k1,’slip 1 with yarn in the back, k1’, repeat ‘-’ until last st, ks
Row 3: knit
Row 4: ks,’slip 1, k1’, repeat ‘-’ until last 2 st, slip 1, ks

and if somebody knows what this pattern is called in English, please let me know