Article day16 (#490)

* written article

* proof read: dense => sparse

* proof read: remove explicit ansers

there are several possible inputs, depending on the user

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Co-authored-by: Jamie Thompson <[email protected]>

Author: iusildra

.gitignore

@@ -6,6 +6,7 @@ target/
 .scala-build
 .scala/
 website/src/js
+.metals
 
 # Dependencies
 website/node_modules
@@ -27,3 +28,6 @@ website/build
 npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
+
+.markdownlint.json
+.vscode