Block trellis (pattern)

A blackwork pattern made up of spaced squares which, when joined, form a cross shape. It is a fairly open pattern and is good for natural designs.
Method
Working vertically, start by filling the area with an even length running stitch, each stitch over and under two threads of the fabric.
Continue working columns, each spaced by four threads of the fabric.
Fill the gaps with horizontal rows of running stitch to form a grid.
Work down each running stitch column adding two horizontal stitches to each gap. Each stitch should be over two threads and spaced by two threads of the fabric.
Continue to fill the area.
Work over the shape again in the opposite orientation to complete small squares.
The completed the pattern.

Structure of stitch
Embroidery Techniques
Identifying Block trellis (pattern)
Rows of squares interconnected by single stitches.
References
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Various Authors, The Royal School of Needlework Book of Embroidery (2018) , p.152
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Becky Hogg, RSN Essential Stitch Guides: Blackwork (2010) , p.70