Author: Chris Noxz <chris@noxz.tech>

diff -upN dwm-6.1/config.def.h dwm-nrowgrid-6.1/config.def.h
--- dwm-6.1/config.def.h	2015-11-08 23:11:48.000000000 +0100
+++ dwm-nrowgrid-6.1/config.def.h	2018-10-01 10:44:05.631382842 +0200
@@ -34,11 +34,15 @@ static const float mfact     = 0.55; /*
 static const int nmaster     = 1;    /* number of clients in master area */
 static const int resizehints = 1;    /* 1 means respect size hints in tiled resizals */
 
+#define FORCE_VSPLIT 1
+#include "nrowgrid.c"
+
 static const Layout layouts[] = {
 	/* symbol     arrange function */
 	{ "[]=",      tile },    /* first entry is default */
 	{ "><>",      NULL },    /* no layout function means floating behavior */
 	{ "[M]",      monocle },
+	{ "###",      nrowgrid },
 };
 
 /* key definitions */
diff -upN dwm-6.1/nrowgrid.c dwm-nrowgrid-6.1/nrowgrid.c
--- dwm-6.1/nrowgrid.c	1970-01-01 01:00:00.000000000 +0100
+++ dwm-nrowgrid-6.1/nrowgrid.c	2018-10-01 10:44:27.741263063 +0200
@@ -0,0 +1,52 @@
+void
+nrowgrid(Monitor *m)
+{
+    unsigned int n = 0, i = 0, ri = 0, ci = 0;  /* counters */
+    unsigned int cx, cy, cw, ch;                /* client geometry */
+    unsigned int uw = 0, uh = 0, uc = 0;        /* utilization trackers */
+    unsigned int cols, rows = m->nmaster + 1;
+    Client *c;
+
+    /* count clients */
+    for (c = nexttiled(m->clients); c; c = nexttiled(c->next), n++);
+
+    /* nothing to do here */
+    if (n == 0)
+        return;
+
+    /* force 2 clients to always split vertically */
+    if (FORCE_VSPLIT && n == 2)
+        rows = 1;
+
+    /* never allow empty rows */
+    if (n < rows)
+        rows = n;
+
+    /* define first row */
+    cols = n / rows;
+    uc = cols;
+    cy = m->wy;
+    ch = m->wh / rows;
+    uh = ch;
+
+    for (c = nexttiled(m->clients); c; c = nexttiled(c->next), i++, ci++) {
+        if (ci == cols) {
+            uw = 0;
+            ci = 0;
+            ri++;
+
+            /* next row */
+            cols = (n - uc) / (rows - ri);
+            uc += cols;
+            cy = m->wy + uh;
+            ch = (m->wh - uh) / (rows - ri);
+            uh += ch;
+        }
+
+        cx = m->wx + uw;
+        cw = (m->ww - uw) / (cols - ci);
+        uw += cw;
+
+        resize(c, cx, cy, cw - 2 * c->bw, ch - 2 * c->bw, 0);
+    }
+}