diff --git a/usage.md b/usage.md
index 7e202eb..45ed196 100644
--- a/usage.md
+++ b/usage.md
@@ -16,8 +16,11 @@ if this filename is an empty string, *stdout* will be used.
 
 ## Use it
 
-- call genp_move(x, y)
-- call genp_draw(x, y, c)
+- real xa, ya, xb, yb
+- integer color
+- call genp_move(xa, ya)
+- call genp_draw(xa, ya, color)
+- call genp_line(xa, ya, xb, yb, color)
 
 ## Terminator