Update README.md

README.md

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 # Observation
 
+## What is this
+
+This is a work in progress project to experiment with [Chain](https://github.com/0xLeif/Chain) and [E.num](https://github.com/0xLeif/E.num) in useful ways.
+
+## Dependencies 
+
+### [E.num](https://github.com/0xLeif/E.num)
+
+#### [Variable](https://github.com/0xLeif/E.num/blob/main/Sources/E/Variable.swift)
+
+```swift
+public enum Variable: Hashable {
+    case void
+    case bool(Bool)
+    case int(Int)
+    case float(Float)
+    case double(Double)
+    case string(String)
+    case set(Set<Variable>)
+    case array([Variable])
+    case dictionary([Variable: Variable])
+}
+```
+
+#### [Function](https://github.com/0xLeif/E.num/blob/main/Sources/E/Function.swift)
+
+```swift
+public enum Function {
+    case void(() -> ())
+    case `in`((Variable) -> ())
+    case out(() -> Variable)
+    case `inout`((Variable) -> Variable)
+}
+```
+
+### [Chain](https://github.com/0xLeif/Chain)
+
+
+```swift
+public indirect enum Chain {
+    case end
+    case complete(E.Function?)
+    case link(E.Function, Chain)
+    case background(E.Function, Chain)
+    case multi([Chain])
+}
+```
+
+
+***
 
 ## Example Code