diff --git a/prototype/Doubt/Vertex.swift b/prototype/Doubt/Vertex.swift
index d5c84bc95..20fb81327 100644
--- a/prototype/Doubt/Vertex.swift
+++ b/prototype/Doubt/Vertex.swift
@@ -32,7 +32,7 @@ public enum Vertex<Element> {
 	public var diagonal: Memo<Vertex> {
 		return right.flatMap { $0.down }
 	}
-	
+
 
 	public init<S1: SequenceType, S2: SequenceType>(rows: S1, columns: S2, combine: (S1.Generator.Element, S2.Generator.Element) -> Element) {
 		let rows = Stream(sequence: rows)