Mosaic Crochet Stitch

Advanced Colorwork

A colorwork technique using elongated stitches worked over previous rows to build sharp, overlaid geometric patterns.

Work your foundation row and first two rows in single or double crochet, alternating one row of each color per the pattern's row count — mosaic patterns are typically worked 2 rows per color.
On the rows worked in a new color, follow your chart to identify which stitches should show the previous row's color instead of the current one.
For each of those stitches, work an elongated double crochet down into the corresponding stitch two rows below, skipping over the stitch directly beneath, drawing the loop up tall enough to sit level with the current row.
Work all other stitches in the row normally, in the current color, per the chart.
Continue alternating two rows per color, always reading the chart to know which stitches drop down to grab the previous color.

Because only one color is ever active per row, mosaic crochet avoids the stranding of Fair Isle and the bobbins of intarsia entirely — the color changes are an illusion created by elongated stitches reaching down.
Mosaic charts read much like cross-stitch charts, with each square representing one stitch and its intended color.
The elongated stitches pull slightly on the rows below, so mosaic crochet fabric is a bit less stretchy than plain single or double crochet of the same size.