Video Tutorial

3,5mm yarn, 3mm needle

Small size

Round 1: Chain 60. Slip stitch with the 1st chain
Round 2: 60 double crochet
Round 3: Repeat 4 (2 double crochet, 1 increase), 36 double crochet, repeat 4 (2 double crochet, 1 increase) (68 stitches)
Round 4: Repeet 4 (3 double crochet, 1 increase), 36 double crochet, repeat 4 (3 double crochet, 1 increase) (76 stitches)
Round 5: Repeat 4 (4 double crochet, 1 increase), 36 double crochet, repeat 4 (4 double crochet, 1 increase) (84 stitches)
Round 6: Repeat 4 (5 double crochet, 1 increase), 36 double crochet, repeat 4 (5 double crochet, 1 increase) (92 stitches)
Round 7: Repeat 4 (6 double crochet, 1 increase), 36 double crochet, repeat 4 (6 double crochet, 1 increase) (100 stitches)
Rounds 8-9: 100 double crochet
Round 10: Repeat 4 (7 double crochet, 1 increase), 36 double crochet, repeat 4 (7 double crochet, 1 increase) (108 stitches)
Rounds 11-12: 108 double crochet
Round 13: Repeat 4 (8 double crochet, 1 increase), 36 double crochet, repeat 4 (8 double crochet, 1 increase) (116 stitches)
Round 14: 116 double crochet
Round 15: Repeat 4 (9 double crochet, 1 increase), 36 double crochet, repeat 4 (9 double crochet, 1 increase) (124 stitches)
Rounds 16-31: 62 double crochet
Round 32: Chain 62, join with the 1st stitch in the 31th round
Round 33: Repeat 4 (9 double crochet, 1 decrease), 36 double crochet, repeat 4 (9 double crochet, 1 decrease) (116 stitches)
Round 34: 116 double crochet
Round 35: Repeat 4 (8 double crochet, 1 decrease), 36 double crochet, repeat 4 (8 double crochet, 1 decrease) (108 stitches)
Rounds 36-37: 108 double crochet
Round 38: Repeat 4 (7 double crochet, 1 decrease), 36 double crochet, repeat 4 (7 double crochet, 1 decrease) (100 stitches)
Rounds 39-40: 100 double crochet
Round 41: Repeat 4 (6 double crochet, 1 decrease), 36 double crochet, repeat 4 (6 double crochet, 1 decrease) (92 stitches)
Round 42: Repeat 4 (5 double crochet, 1 decrease), 36 double crochet, repeat 4 (5 double crochet, 1 decrease) (84 stitches)
Round 43: Repeat 4 (4 double crochet, 1 decrease), 36 double crochet, repeat 4 (4 double crochet, 1 decrease) (76 stitches)
Round 44: Repeat 4 (3 double crochet, 1 decrease), 36 double crochet, repeat 4 (3 double crochet, 1 decrease) (68 stitches)
Round 45: Repeat 4 (2 double crochet, 1 decrease), 36 double crochet, repeat 4 (2 double crochet, 1 decrease) (60 stitches)
Round 46: 60 double crochet

Medium Size

Round 1: Chain 70. Slip stitch
Round 2: 70 double crochet
Round 3: Repeat 4 (2 double crochet, 1 increase), 46 double crochet, repeat 4 (2 double crochet, 1 increase) (78 stitches)
Round 4: Repeat 4 (3 double crochet, 1 increase), 46 double crochet, repeat 4 (3 double crochet, 1 increase) (86 stitches)
Round 5: Repeat 4 (4 double crochet, 1 increase), 46 double crochet, repeat 4 (4 double crochet, 1 increase) (94 stitches)
Round 6: Repeat 4 (5 double crochet, 1 increase), 46 double crochet, repeat 4 (5 double crochet, 1 increase) (102 stitches)
Round 7: Repeat 4 (6 double crochet, 1 increase), 46 double crochet, repeat 4 (6 double crochet, 1 increase) (110 stitches)
Rounds 8-9: 110 double crochet
Round 3: Repeat 4 (7 double crochet, 1 increase), 46 double crochet, repeat 4 (7 double crochet, 1 increase) (118 stitches)
Rounds 11-12: 118 double crochet
Round 13: Repeat 4 (8 double crochet, 1 increase), 46 double crochet, repeat 4 (8 double crochet, 1 increase) (126 stitches)
Round 14: 126 double crochet
Round 15: Repeat 4 (9 double crochet, 1 increase), 46 double crochet, repeat 4 (9 double crochet, 1 increase) (134 stitches)
Round 16: Repeat 4 (10 double crochet, 1 increase), 46 double crochet, repeat 4 (10 double crochet, 1 increase) (142 stitches)
Rounds 17-35: 71 double crochet
Round 36: Chain 71. Slip stitch with the 1st 35 round stitch
Round 37: Repeat 4 (10 double crochet, 1 decrease), 46 double crochet, repeat 4 (10 double crochet, 1 decrease) (134 stitches)
Round 38: Repeat 4 (9 double crochet, 1 decrease), 46 double crochet, repeat 4 (9 double crochet, 1 decrease) (126 stitches)
Round 39: 126 double crochet
Round 40: Repeat 4 (8 double crochet, 1 decrease), 46 double crochet, repeat 4 (8 double crochet, 1 decrease) (118 stitches)
Rounds 41-42: 118 double crochet 
Round 43: Repeat 4 (7 double crochet, 1 decrease), 46 double crochet, repeat 4 (7 double crochet, 1 decrease) (110 stitches)
Rounds 44-45: 110 double crochet
Round 46: Repeat 4 (6 double crochet, 1 decrease), 46 double crochet, repeat 4 (6 double crochet, 1 decrease) (102 stitches)
Round 47: Repeat 4 (5 double crochet, 1 decrease), 46 double crochet, repeat 4 (5 double crochet, 1 decrease) (94 stitches)
Round 48: Repeat 4 (4 double crochet, 1 decrease), 46 double crochet, repeat 4 (4 double crochet, 1 decrease) (86 stitches)
Round 49: Repeat 4 (3 double crochet, 1 decrease), 46 double crochet, repeat 4 (3 double crochet, 1 decrease) (78 stitches)
Round 50: Repeat 4 (2 double crochet, 1 decrease), 46 double crochet, repeat 4 (2 double crochet, 1 decrease) (70 stitches)
Round 51: 70 double crochet

Large Size

Round 1: Chain 80. Slip stitch
Round 2: 80 double crochet
Round 3: Repeat 4 (2 double crochet, 1 increase), 56 double crochet, repeat 4 (2 double crochet, 1 increase) (88 stitches)
Round 4: Repeat 4 (3 double crochet, 1 increase), 56 double crochet, repeat 4 (3 double crochet, 1 increase) (96 stitches)
Round 5: Repeat 4 (4 double crochet, 1 increase), 56 double crochet, repeat 4 (4 double crochet, 1 increase) (104 stitches)
Round 6: Repeat 4 (5 double crochet, 1 increase), 56 double crochet, repeat 4 (5 double crochet, 1 increase) (112 stitches)
Round 7: Repeat 4 (6 double crochet, 1 increase), 56 double crochet, repeat 4 (6 double crochet, 1 increase) (120 stitches)
Rounds 8-10: 120 double crochet
Round 11: Repeat 4 (7 double crochet, 1 increase), 56 double crochet, repeat 4 (7 double crochet, 1 increase) (128 stitches)
Rounds 12-13: 128 double crochet
Round 14: Repeat 4 (8 double crochet, 1 increase), 56 double crochet, repeat 4 (8 double crochet, 1 increase) (136 stitches)
Rounds 15-16: 136 double crochet
Round 17: Repeat 4 (9 double crochet, 1 increase), 56 double crochet, repeat 4 (9 double crochet, 1 increase) (144 stitches)
Round 18: Repeat 4 (10 double crochet, 1 increase), 56 double crochet, repeat 4 (10 double crochet, 1 increase) (152 stitches)
Round 19: 152 double crochet
Rounds 20-40: 76 double crochet
Round 41: Chain 76. Slip stitch with the 1st 40 round stitch
Round 42: 152 double crochet
Round 43: Repeat 4 (10 double crochet, 1 decrease), 56 double crochet, repeat 4 (10 double crochet, 1 decrease) (144 stitches)
Round 44: Repeat 4 (9 double crochet, 1 decrease), 56 double crochet, repeat 4 (9 double crochet, 1 decrease) (136 stitches)
Rounds 45-46: 136 double crochet
Round 47: Repeat 4 (8 double crochet, 1 decrease), 56 double crochet, repeat 4 (8 double crochet, 1 decrease) (128 stitches)
Rounds 48-49: 118 double crochet
Round 50: Repeat 4 (7 double crochet, 1 decrease), 56 double crochet, repeat 4 (7 double crochet, 1 decrease) (120 stitches)
Rounds 51-52: 120 double crochet
Round 53: Repeat 4 (6 double crochet, 1 decrease), 56 double crochet, repeat 4 (6 double crochet, 1 decrease) (112 stitches)
Round 54: Repeat 4 (5 double crochet, 1 decrease), 56 double crochet, repeat 4 (5 double crochet, 1 decrease) (104 stitches)
Round 55: Repeat 4 (4 double crochet, 1 decrease), 56 double crochet, repeat 4 (4 double crochet, 1 decrease) (96 stitches)
Round 56: Repeat 4 (3 double crochet, 1 decrease), 56 double crochet, repeat 4 (3 double crochet, 1 decrease) (88 stitches)
Round 57: Repeat 4 (2 double crochet, 1 decrease), 56 double crochet, repeat 4 (2 double crochet, 1 decrease) (80 stitches)Round 58: 80 double crochet