added some ideas

README.md

 # sandcastle
 
-A castle in a sandbox.
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+A castle in a sandbox.
+
+## Abstract
+
+_Sandcastle_ is sort of a playground for a _server_ and _client_ programming environment.
+
+The _server_ component provides several services that can be consumed be _clients_. The _clients_
+can be `telnet`, `ssh`, a _web browser_, or a _special client_. Another _special client_ could also
+be another _server_, to distribute the load.
+
+## Features
+
+### Server features
+
+* support for different listeners
+    * `telnet`
+    * `ssh`
+    * `http` and `https` for _web browsers_ (`lynx`?)
+    * a special client written in [Go][]
+* use _goroutines_ for maximum resource usage
+
+### Client features
+
+* **TBD**
+
+<!-- Links -->
+
+[Go]: https://golang.org/
+
+<!-- End Of File -->
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