Added an example of a "multiline if block".

CONTRIBUTING.md

@@ -3,8 +3,28 @@ Coding conventions
 
 * Use tabs to indent, spaces to align.
 	* Specifically, spaces should not appear at the beginning of a line, and tabs should not appear _except_ at the beginning of a line.
-	* The sole exception is in a multiline `if` statement; the initial `if` should have four spaces before it to align it with an `elseif` on the next line.
-	* Comments with lines at the end of code must be one line long. Multi-line comments must appeare in their own block.
+	* The sole exception is in a multiline `if` statement; the initial `if` should have four spaces before it to align it with an `elseif` on the next line. For example:
+
+```lua
+	    if self.level <  900 then return 12
+	elseif self.level < 1200 then return 8
+	else return 6 end
+```
+
+* Comments at the end of lines of code must be one line long. Multi-line comments must appear in their own block.
+
+```lua
+	if self.piece:isDropBlocked(self.grid) then
+		-- for bottomed out pieces, decrease the drop bonus if they stall on dropping it
+		self.drop_bonus = math.min(self.drop_bonus - 1, 0) -- by 1 point per frame
+	else                                                            
+		if piece_dy >= 1 then                                       -- basically
+			self.drop_bonus = self.drop_bonus + piece_dy * 20       -- this sort of
+		end                                                         -- multiline comment
+		self.drop_bonus = self.drop_bonus + 1                       -- is completely
+	end                                                             -- unacceptable
+```
+
 * Use `snake_case` for variables, `camelCase` for functions.
 
 
@@ -15,4 +35,4 @@ By contributing source code or other assets (e.g. music, artwork, graphics) to C
 
 You also waive all moral rights to your contributions insofar as they are used in the Cambridge repository or in any code or works deriving therefrom.
 
-(Regarding the above clause, I will still make my best effort to provide sufficient attribution to all contributions. At the very least you'll get documentation of your contributions under SOURCES, and probably a special place in the credit roll as well.)
+(Notwithstanding the above clause, I will still make my best effort to provide sufficient attribution to all contributions. At the very least you'll get documentation of your contributions under SOURCES, and probably a special place in the credit roll as well.)