Make 2 in desired colours.

With K cro-hook and one strand of yarn, ch 49.
Row 1 {1st half}: Insert hk in 2nd ch from hk, yo and draw lp through, keeping lp on hk {2 lps now on hk}, * draw up a lp in next ch and keep lp on hk; rep from * across. Drop yarn, DO NOT CUT. Slide work to other end of hk and turn. [49 lps on hk]
Row 1 {2nd half}: With 2nd ball of yarn, yo and draw through 1st lp on hk, * yo and draw through 2 lps on hk; rep from * across until 1 lp remains on hk. This lp counts as first lp of next row. DO NOT TURN. [1 lp on hk]
Row 2 {1st half}: Continuing with same yarn as 2nd half of previous row, * draw up a lp in next horizontal bar and keep lp on hk; rep from * across. Drop yarn, DO NOT CUT. Slide work to other end of hk and turn. [49 lps on hk]
Row 2 {2nd half}: Pick up 1st ball of yarn and work off lps in same manner as 2nd half of Row 1. At end of row, DO NOT TURN. [1 lp on hk]
Row 3 {1st half}: Continuing with same yarn as 2nd half of previous row, draw up a lp in next horizontal bar and keep lp on hk; yo, and draw up a lp in 3rd vertical bar of previous row, yo, draw through 2 lps on hk; * sk next horizontal bar, draw up a lp in next horizontal bar (3 times); yo, sk next 3 vertical bars of previous row, draw up a lp in next vertical bar of previous row, yo, draw through 2 lps on hook; rep from * across, sk next horizontal bar, draw up a loop in last 2 horizontal bars. Drop yarn, DO NOT CUT. Slide work to other end of hk and turn. [49 lps on hk]
Row 3 {2nd half}: Pick up 1st ball of yarn and work off lps in same manner as 2nd half of Row 1. At end of row, DO NOT TURN. [1 lp on hk]
Row 4 {both halves}: Repeat row 3.
Row 5 {1st half}: Continuing with same yarn as 2nd half of previous row, draw up a lp in next horizontal bar and keep lp on hk (3 times); yo, and draw up a lp in 3rd vertical bar of previous row, yo, draw through 2 lps on hk; * sk next horizontal bar, draw up a lp in next horizontal bar (3 times); yo, sk next 3 vertical bars of previous row, draw up a lp in next vertical bar of previous row, yo, draw through 2 lps on hook; rep from * across, sk next horizontal bar, draw up a loop in last 4 horizontal bars. Drop yarn, DO NOT CUT. Slide work to other end of hk and turn. [49 lps on hk]
Row 5 {2nd half}: Pick up 1st ball of yarn and work off lps in same manner as 2nd half of Row 1. At end of row, DO NOT TURN. [1 lp on hk]
Row 6 {both halves}: Repeat row 5.
Repeat Rows 3-6 until piece measures between 11½" and 12" from beg edge without stretching fabric, ending with the same colour you began the square with if possible.
Last Row: Replace cro-hook with conventional crochet hook. Ch 1, sc (or sl st) in first horizontal bar and each horizontal bar across. Finish off and weave in ends.

NOTE: You will work the 2nd half of one row, and the 1st half of the next using the same colour of yarn -- colour/ yarn switching occurs halfway through completing each row. An easy way to remember is that you work off lps with a different colour than the lps are, and you pick up lps with the same colour that you worked the lps off with. Additionally, the "weaves" from the current row should fall in the middle of the previous row's "weaves".