diff --git a/mermaid.go b/mermaid.go
index 9b2d3a6..df4fa07 100644
--- a/mermaid.go
+++ b/mermaid.go
@@ -80,11 +80,28 @@ func diagramGraph(g *Graph, sb *strings.Builder) {
 		nodeShape := MermaidShapeRound
 		each := g.nodes[key]
 		if s := each.GetAttr("shape"); s != nil {
-			nodeShape = s.(shape)
+			// could be a shape or a string
+			shapeString, ok := s.(string)
+			if ok {
+				// see if we can map the string to a shape
+				mermaidShape, ok := lookupShape(shapeString)
+				if ok {
+					nodeShape = mermaidShape
+				}
+			}
+			// could be a shape
+			mermaidShape, ok := s.(shape)
+			if ok {
+				nodeShape = mermaidShape
+			}
 		}
 		txt := "?"
 		if label := each.GetAttr("label"); label != nil {
-			txt = label.(string)
+			// take string only
+			slabel, ok := label.(string)
+			if ok {
+				txt = slabel
+			}
 		}
 		fmt.Fprintf(sb, "\tn%d%s%s%s;\n", each.seq, nodeShape.open, escape(txt), nodeShape.close)
 		if style := each.GetAttr("style"); style != nil {
@@ -103,11 +120,16 @@ func diagramGraph(g *Graph, sb *strings.Builder) {
 			// The edge can override the link style
 			link := denoteEdge
 			if l := each.GetAttr("link"); l != nil {
-				link = l.(string)
+				// take string only
+				slink, ok := l.(string)
+				if ok {
+					link = slink
+				}
 			}
 			if label := each.GetAttr("label"); label != nil {
 				slabel, ok := label.(string)
 				if !ok {
+					// make it a string
 					slabel = fmt.Sprintf("%v", label)
 				}
 				if label != "" {
@@ -124,3 +146,33 @@ func diagramGraph(g *Graph, sb *strings.Builder) {
 func writeEnd(sb *strings.Builder) {
 	sb.WriteString(";\n")
 }
+
+func lookupShape(shapeName string) (shape, bool) {
+	switch shapeName {
+	case "round", "box":
+		return MermaidShapeRound, true
+	case "asymmetric":
+		return MermaidShapeAsymmetric, true
+	case "circle":
+		return MermaidShapeCircle, true
+	case "cylinder":
+		return MermaidShapeCylinder, true
+	case "rhombux":
+		return MermaidShapeRhombus, true
+	case "stadium":
+		return MermaidShapeStadium, true
+	case "subroutine":
+		return MermaidShapeSubroutine, true
+	case "trapezoid":
+		return MermaidShapeTrapezoid, true
+	case "trapezoid-alt":
+		return MermaidShapeTrapezoidAlt, true
+	case "hexagon":
+		return MermaidShapeHexagon, true
+	case "parallelogram":
+		return MermaidShapeParallelogram, true
+	case "parallelogram-alt":
+		return MermaidShapeParallelogramAlt, true
+	}
+	return shape{}, false
+}
diff --git a/mermaid_test.go b/mermaid_test.go
index 16e5b7c..5fc7d6e 100644
--- a/mermaid_test.go
+++ b/mermaid_test.go
@@ -97,3 +97,45 @@ func TestMermaidSubgraph(t *testing.T) {
 		t.Errorf("got [%[1]v:%[1]T] want [%[2]v:%[2]T]", got, want)
 	}
 }
+
+func TestMermaidFromBoxShape(t *testing.T) {
+	graph := NewGraph(Directed)
+	graph.Node("A").Box()
+	graph.Edge(graph.Node("A"), graph.Node("B"))
+
+	if got, want := flatten(MermaidGraph(graph, MermaidTopDown)), `graph TD;n1("A");n2("B");n1-->n2;`; got != want {
+		t.Errorf("got [%[1]v:%[1]T] want [%[2]v:%[2]T]", got, want)
+	}
+}
+func TestLookupShape(t *testing.T) {
+	tests := []struct {
+		name      string
+		shapeName string
+		wantShape shape
+		wantOk    bool
+	}{
+		{"round", "round", MermaidShapeRound, true},
+		{"box", "box", MermaidShapeRound, true},
+		{"asymmetric", "asymmetric", MermaidShapeAsymmetric, true},
+		{"circle", "circle", MermaidShapeCircle, true},
+		{"cylinder", "cylinder", MermaidShapeCylinder, true},
+		{"rhombux", "rhombux", MermaidShapeRhombus, true},
+		{"stadium", "stadium", MermaidShapeStadium, true},
+		{"subroutine", "subroutine", MermaidShapeSubroutine, true},
+		{"trapezoid", "trapezoid", MermaidShapeTrapezoid, true},
+		{"trapezoid-alt", "trapezoid-alt", MermaidShapeTrapezoidAlt, true},
+		{"hexagon", "hexagon", MermaidShapeHexagon, true},
+		{"parallelogram", "parallelogram", MermaidShapeParallelogram, true},
+		{"parallelogram-alt", "parallelogram-alt", MermaidShapeParallelogramAlt, true},
+		{"unknown", "unknown", shape{}, false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotShape, gotOk := lookupShape(tt.shapeName)
+			if gotShape != tt.wantShape || gotOk != tt.wantOk {
+				t.Errorf("lookupShape(%q) = (%v, %v), want (%v, %v)", tt.shapeName, gotShape, gotOk, tt.wantShape, tt.wantOk)
+			}
+		})
+	}
+}