Classic flowchart (with proper symbols)

{
  "nodes": [
    { "id":"st","type":"ellipse","label":"Start","x":40,"y":160,"fill":"#dcfce7","stroke":"#15803d" },
    { "id":"in","type":"parallelogram","label":"Read order","x":220,"y":160,"fill":"#dbeafe","stroke":"#2563eb" },
    { "id":"pr","type":"hexagon","label":"Prepare","x":420,"y":160,"fill":"#fef3c7","stroke":"#a16207" },
    { "id":"pc","type":"rounded","label":"Validate","x":620,"y":160,"fill":"#fed7aa","stroke":"#c2410c" },
    { "id":"de","type":"diamond","label":"Valid?","x":820,"y":145,"fill":"#fef3c7","stroke":"#a16207" },
    { "id":"pr2","type":"rounded","label":"Process","x":1040,"y":80,"fill":"#dbeafe","stroke":"#2563eb" },
    { "id":"err","type":"triangle","label":"Error","x":1040,"y":260,"fill":"#fee2e2","stroke":"#b91c1c" },
    { "id":"out","type":"document","label":"Receipt","x":1240,"y":80,"fill":"#ede9fe","stroke":"#6d28d9" },
    { "id":"end","type":"ellipse","label":"End","x":1440,"y":160,"fill":"#dcfce7","stroke":"#15803d" }
  ],
  "edges": [
    { "id":"e1","source":"st","target":"in" },
    { "id":"e2","source":"in","target":"pr" },
    { "id":"e3","source":"pr","target":"pc" },
    { "id":"e4","source":"pc","target":"de" },
    { "id":"e5","source":"de","target":"pr2","label":"yes" },
    { "id":"e6","source":"de","target":"err","label":"no" },
    { "id":"e7","source":"pr2","target":"out" },
    { "id":"e8","source":"out","target":"end" },
    { "id":"e9","source":"err","target":"pc","label":"retry" }
  ]
}