diff --git a/layout.sty b/layout.sty
index 0442c2a2dc0c4a10aa445c0d80a683893dc2dfac..d9dd3bb4b02a8ee4784d970d36a5d487a3588344 100644
--- a/layout.sty
+++ b/layout.sty
@@ -570,6 +570,8 @@ interior code={ \path[tcb fill interior] ([xshift=-2mm]interior.west)
 \makeindex
 \raggedbottom
 
+\newcolumntype{Y}{>{\centering\arraybackslash}X}
+
 \newcommand{\currentsphere}{magic}
 
 \newcommand{\sphere}[1]{%