##Change default block alignment
##block alignment left right top bottom default diagonal
##Left-to-right default layout achieved by assigning 'mleft=prev@mright' and 'middle=prev@middle' with a lower priority than attributes specified directly. Top-to-bottom uses 'mtop=prev@mbottom' and 'center=prev@center' - essentially the content of the 'col' style. Setting 'mleft' (or 'left' to exclude margins) in a column setting will have higher priority than the default and will override the 'center=prev@center' and result in diagonal layout.
box: A;
box: B;   #follows in a row
use col;
box: C;   #follows in a col
box: D;   #follows in a col
use mleft=prev@mright;
box: E;   #follows diagonally
box: F;   #follows diagonally