diff --git a/.gitignore b/.gitignore
index 84c048a..4d37447 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,5 @@
 /build/
+
+# A built binary. The lab writes one here when pointed at the repository root by mistake;
+# built artifacts belong in build/, which is already ignored.
+/mesh-builder
diff --git a/mesh-builder b/mesh-builder
deleted file mode 100755
index 13be1c2..0000000
Binary files a/mesh-builder and /dev/null differ