diff --git a/bricks/imgs/left-bottom-triangle.png b/bricks/imgs/left-bottom-triangle.png
new file mode 100644
index 0000000..feb1db6
Binary files /dev/null and b/bricks/imgs/left-bottom-triangle.png differ
diff --git a/bricks/imgs/left-top-triangle.png b/bricks/imgs/left-top-triangle.png
new file mode 100644
index 0000000..fc0d8d8
Binary files /dev/null and b/bricks/imgs/left-top-triangle.png differ
diff --git a/bricks/imgs/right-bottom-triangle.png b/bricks/imgs/right-bottom-triangle.png
new file mode 100644
index 0000000..ce4f7b7
Binary files /dev/null and b/bricks/imgs/right-bottom-triangle.png differ
diff --git a/bricks/imgs/right-top-triangle.png b/bricks/imgs/right-top-triangle.png
new file mode 100644
index 0000000..2b1299d
Binary files /dev/null and b/bricks/imgs/right-top-triangle.png differ