<HTML> <HEAD> <TITLE>block</TITLE></HEAD> <BODY> <h1>block</h1> <B>Category</B><p> <a href="object_commands.html">Object/view commands</a><p> <B>Syntax</B><p> <p> block(X1,Y1,X2,Y2);<p> <B>Description</B><p> <p> This sets up an invisible rectangular block on the screen with top-left co-ordinates X1,Y1 and bottom-right co-ordinates X2,Y2. Objects are not allowed to cross the borders of this block (unless they are told to ignore blocks). The block can be removed using the <a href="unblock.html">unblock</a> command. <p> Note: You can only have one block on the screen at a time. If a block already exists, and you use the block command again, the new block will be there but the old one will be gone.<p> <B>See also</B><p> <a href="unblock.html">unblock</a><p> <a href="ignore_blocks.html">ignore.blocks</a><p> <a href="observe_blocks.html">observe.blocks</a><p> <a href="controlling_obstacles.html">Controlling obstacles</a><p> </BODY></HTML>