diff --git a/openrndr-demos/src/demo/kotlin/DemoLineCapJoin.kt b/openrndr-demos/src/demo/kotlin/DemoLineCapJoin.kt
new file mode 100644
index 00000000..8141a882
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+++ b/openrndr-demos/src/demo/kotlin/DemoLineCapJoin.kt
@@ -0,0 +1,54 @@
+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.draw.LineCap
+import org.openrndr.draw.LineJoin
+import org.openrndr.draw.isolated
+import org.openrndr.draw.loadFont
+import org.openrndr.math.IntVector2
+import org.openrndr.math.Vector2
+import org.openrndr.shape.Triangle
+
+/**
+ * Test all combinations of line cap and line join by drawing
+ * a 3x3 grid of triangles and lines.
+ */
+
+fun main() {
+    application {
+        configure {
+            width = 720
+            height = 720
+        }
+
+        program {
+            val font = loadFont("demo-data/fonts/IBMPlexMono-Regular.ttf", 20.0)
+            val pointA = Vector2(0.0, 50.0)
+            val pointB = Vector2(50.0, -20.0)
+            val pointC = Vector2(-50.0, 0.0)
+            val triangle = Triangle(pointA, pointB, pointC).contour
+
+            extend {
+                drawer.apply {
+                    fill = ColorRGBa.GRAY
+                    stroke = ColorRGBa.PINK
+                    strokeWeight = 8.0
+                    fontMap = font
+                    LineCap.values().forEachIndexed { x, cap ->
+                        lineCap = cap
+                        LineJoin.values().forEachIndexed { y, join ->
+                            lineJoin = join
+                            val pos = IntVector2(x - 1, y - 1).vector2 * 180.0
+                            isolated {
+                                translate(bounds.position(0.46, 0.46) + pos)
+                                text("cap: ${cap.name}", -30.5, 80.5)
+                                text("join: ${join.name}", -30.5, 100.5)
+                                contour(triangle)
+                                lineSegment(pointA - pointC, pointB - pointC)
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
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