Extension task.HEADmaster

1 files changed, 16 insertions, 7 deletions

diff --git a/presentation.md b/presentation.md
index d11a818..ef2fcce 100644
--- a/presentation.md
+++ b/presentation.md
@@ -15,13 +15,14 @@ Discuss
 * What makes a good paper plane?
 
 # The value of a paper plane
+
 A paper plane can model a real plane, with limited resources and with
-relative ease. Paper has a similar in-scale to weight to strength
-ratio of aluminium which real planes are made of.
+relative ease. Paper has a weight to strength ratio similar to
+aluminium which real planes are made of.
 
-During the Great Depression, designers used
-paper models to design planes that were later used very effectively by
-the Nazis in World War Two.
+During the Great Depression, designers used paper models to help
+design planes that were later used very effectively by the Nazis in
+World War Two.
 
 # Initial designs
 
@@ -30,13 +31,21 @@ about why certain designs might fly better.
 
 # The classic design
 ![Classical Plane
-Design](https://upload.wikimedia.org/wikipedia/commons/c/c4/Paper_Airplane.png){ width=50% }
+Design](plane.png){ width=50% }
 
 # A different design
 John Collins designed the current world record plane for distance.
 
-(Optional) See the world record throw: <https://www.youtube.com/watch?v=cXqwUxkNXVE>
+(Optional) Watch the world record throw: <https://www.youtube.com/watch?v=cXqwUxkNXVE>
 
 Folding the record plane(starts itself at 2:50, watch as much as you
 want)
 <https://www.youtube.com/watch?v=3BNg4fDJC8A&t=170>
+
+# Extension: more designs
+
+Check out <https://www.foldnfly.com>, the instructions are not perfect
+but there are quite a few planes.
+
+The loop plane is pretty good
+<https://www.foldnfly.com/46.html#Loop-Plane>