diff --git a/src/Flux.jl b/src/Flux.jl
index 610f13db..bee668ec 100644
--- a/src/Flux.jl
+++ b/src/Flux.jl
@@ -7,12 +7,13 @@ using MacroTools, Lazy, Flow
 export Model, back!, update!
 
 abstract Model
-abstract Capacitor <: Model
 abstract Activation <: Model
 
 back!(m::Model, ∇) = error("Backprop not implemented for $(typeof(m))")
 update!(m::Model, η) = m
 
+include("capacitor.jl")
+
 include("compiler/diff.jl")
 include("compiler/loop.jl")
 include("compiler/code.jl")
diff --git a/src/capacitor.jl b/src/capacitor.jl
new file mode 100644
index 00000000..43204f27
--- /dev/null
+++ b/src/capacitor.jl
@@ -0,0 +1,8 @@
+type Capacitor{T}
+  Δs::Vector{T}
+end
+
+type Patch{T}
+  η::Float32
+  Δs::Capacitor{T}
+end
diff --git a/src/layers/sequence.jl b/src/layers/sequence.jl
index f80fcbfb..fc1c4f6c 100644
--- a/src/layers/sequence.jl
+++ b/src/layers/sequence.jl
@@ -1,6 +1,6 @@
 export Sequence
 
-type Sequence <: Capacitor
+type Sequence
   layers::Vector{Model}
 end