added design doc

diff --git a/docs/tower_defense b/docs/tower_defense
index 731316df37ebc58c12599a61dee18fc22b7f2844..6dda2b6cc90e14393a9a6c96fb7ccbf892f87292 100644 (file)
--- a/docs/tower_defense
+++ b/docs/tower_defense
@@ -15,3 +15,11 @@ Unlock things such as:
 Programming will be on a SCRATCH like iterface (i.e. no typing the code)
 Connect logic blocks and sensors
 More like FRP, but not because no one knows what that is
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+Analog vs Digital Wires?
+Should the wires represent a digital (1 or 0) signal, or an analog one (continuous between 0 and 1).
+Analog would be more interesting, but more complicated to build things with.