This is a great pattern for beginning crocheters to practice single crochet and double crochet. The pattern is very easy but has a more interesting design than row after row of just single crochet (which is ok sometimes but can become boring too). Beginners often ask for very easy patterns that will still hold their interest. This pattern can be an answer for that.
I've provided extra explanation before the pattern directions and have given links within the directions, to help explain parts that there could be questions about.
Abbreviations: ch = chain, chs = chains, ea = each, dc = double crochet, sc = single crochet, st = stitch, sts = stitches
Materials: about 1 oz. any weight of yarn. I used worsted weight yarn and a US size J hook for about 8 1/2 inches square (a US H or I hook could be used with worsted weight yarn instead, to result in a size that is a bit smaller).
You can make this all in one color or use several colors, as shown in the photo example. If you are a beginner, I'd recommend making the square all in one color the first time that you crochet this square, then try it with several colors, if you're interested in that look. In the example, in the middle section, I crocheted two rows of each color (by doing two rows before changing colors, the unused color can be carried along one edge and crocheted over when doing the final outside round, making less ends to weave in later).
Changing to a New Color for the Next Row: If you use more than one color in your square, on the last stitch of the row before the new color, do the last loop of the stitch in the new color, for a smooth transition to the new color. In other words, part of the sc or dc is made in the color you were using and the last loop of the sc or dc is in the new color. If you're not familiar with this, see: Changing Colors, Illustrated.
Pattern Notes for Beginners: You will turn at the end of each row (which means to turn the piece over so that the opposite side of the piece is facing you; in other words, if the right side of the piece was facing you in the row just completed, then the wrong side of the piece should be facing you after you turn the piece over to begin the next row).
Row 2 Note For Beginners: It's a good idea to count the stitches as you go along for a few rows until you have the pattern established for the square. You should have 8 stitches in each of the three sections, with 24 stitches total in the row. If you have too many stitches at the end of the row, you might be making the dc after the turning chain-3 in the same place as the chain-3 (it should be made in the second sc of the previous row). To see a photo showing what that means, see: 2nd dc of the row, close look photo.
Row 3 Note: If you find that you have too few stitches made in a row, you might be accidentally skipping crocheting into what counts as the last dc of the row (which was the turning chain-3 of the previous row and looks different than the rest of the dc stitches). To see a photo showing what this means and a close-up showing what that chain-3 looks like, see chain-3 counting as last dc of the row.
Starting Chain: ch 25.
Row 1 Note: (Work in one loop of ea ch so there will be remaining loops in which to work the outside round when the rows of the square are finished).
Row 1 Directions:sc in second ch from hook, sc in ea of next 7 chs, dc in ea of next 8 chs, sc in ea of next 8 chs. (making 24 sts altogether)
Row 2: ch 3 (counts as first dc), dc in ea of next 7 sc, sc in ea of next 8 dc, dc in ea of next 8 sc.
Row 3: ch 1 (to turn), sc in ea of first 8 dc, dc in ea of next 8 sc, sc in ea of next 8 dc.
Rows 4 - 17: Repeat rows 2 and 3. If you get tired of counting to 8 for each section, here's a note to make it easier to notice when you are changing from sc to dc (and vice versa) in the three sections across a row: note that you will always be making single crochet in double crochet and will always be making double crochet in single crochet (the type of stitch used in a section alternates from row to row).
Row 18: Repeat row 2.
Last Row: ch 1 (to turn), sc in ea st across.
Outside Round: ch 1, then working down the side of the square, make an sc around the edge sc (of rows which ended with an sc) and two sc around the post of the edge dc (of rows which ended with a dc). Be careful to only do one sc for each sc row and 2 sc for each dc row (it can be easy to accidentally work extra sc in some of the little spaces between the rows, which would make the edge a bit wavy from too many sc made along the side). For a corner, ch 2. Along the bottom edge, make an sc in the remaining loop left from ea ch of the starting chain. ch 2 for next corner. Work along the next side in the same manner as the first side. If you used two colors and carried strands along this side, crochet over those strands while making the sc stitches on this side. ch 2 for next corner. sc in ea sc across the top edge, then ch 2 for last corner and slip stitch in the first sc of this round.
End off, leaving a strand for weaving in. Weave in the ends, to secure.