---
# System prepended metadata

title: Untitled

---

h1



## h21121




12121





```vega
{
  "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
  "description": "Plots two functions using a generated sequence.",
  "width": 300,
  "height": 150,
  "data": {
    "sequence": {
      "start": 0,
      "stop": 12.7,
      "step": 0.1,
      "as": "x"
    }
  },
  "transform": [
    {
      "calculate": "sin(datum.x)",
      "as": "sin(x)"
    },
    {
      "calculate": "cos(datum.x)",
      "as": "cos(x)"
    },
    {
      "fold": ["sin(x)", "cos(x)"]
    }
  ],
  "mark": "line",
  "encoding": {
    "x": {
      "type": "quantitative",
      "field": "x"
    },
    "y": {
      "field": "value",
      "type": "quantitative"
    },
    "color": {
      "field": "key",
      "type": "nominal",
      "title": null
    }
  }
}
```
:::spoiler
hide me
:::

```graphviz
digraph {
  compound=true
  rankdir=RL

  graph [ fontname="Source Sans Pro", fontsize=20 ];
  node [ fontname="Source Sans Pro", fontsize=18];
  edge [ fontname="Source Sans Pro", fontsize=12 ];


  subgraph core {
    c [label="Hackmd-it \ncore"] [shape=box]
  }
  
  c -> sync [ltail=session lhead=session]

  subgraph cluster1 {
     concentrate=true
    a [label="Text source\nGithub, Gitlab, ..."] [shape=box]
    b [label="HackMD Editor"] [shape=box]
    sync [label="sync" shape=plaintext ]
    b -> sync  [dir="both"]
    sync -> a [dir="both"]
    label="An edit session"
  }
}
```

