From a Mermaid class diagram

A class diagram imported from Mermaid. Every Mermaid relation operator, imported as diago relations.

                               ┌────────┐                    ┌──────┐     ┌──────┐
                               │ Shape  │                    │ Club │     │ Vet  │
                               └────────┘                    └──────┘     └──────┘
                                  △  △                           ◇ 0..1     │  │
                                  ╎  ╎                           │ members  │  │
                      ┌╌╌╌╌╌╌╌╌╌╌╌┘  ╎                           │          │  └────────────────────┐
                      ╎              ╎                           │ *        │                       │
  ┌────────┐     ┌────────┐     ┌────────┐     ┌──────┐     ┌────────┐      │                  ┌────────┐
  │ Animal │     │ Circle │     │ Square │     │ Pet  │     │ Owner  │      │                  │ Clinic │
  └────────┘     └────────┘     └────────┘     └──────┘     └────────┘      │ treats           └────────┘
       △                                           △       keeps ◆ 1        │
       │                                           │             │     many │
       │                                           │             └────────┐ │
       │                                           └─────────────────────┐│ │
       └───────────────────────────────────────────────────────────────┐ ││ │
                                                                       │ ││ ▼
                                                                       ┌──────┐
                                                                       │ Dog  │
                                                                       └──────┘
                                                                        ◆◇ │ ╎╎
                                                                        ││ │ ╎╎
                                       ┌────────────────────────────────┘│ │ ╎└╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┐
                                       │             ┌───────────────────┘ │ └╌╌╌╌╌╌╌╌╌╌┐              ╎
                                       │             │                     ▼            ▼ eats         ▼
                                  ┌────────┐     ┌──────┐              ┌──────┐     ┌──────┐     ┌──────────┐
                                  │ Kennel │     │ Toy  │              │ Bowl │     │ Food │     │ Groomer  │
                                  └────────┘     └──────┘              └──────┘     └──────┘     └──────────┘

Spec

Mermaid
JSON

classDiagram
  Animal <|-- Dog
  Dog --|> Pet
  Shape <|.. Circle
  Square ..|> Shape
  Owner "1" *-- "many" Dog : keeps
  Kennel --* Dog
  Club "0..1" o-- "*" Owner : members
  Toy --o Dog
  Vet --> Dog : treats
  Bowl <-- Dog
  Dog ..> Food : eats
  Groomer <.. Dog
  Vet -- Clinic

{
  "type": "class",
  "classes": [
    {"id": "Animal"},
    {"id": "Dog"},
    {"id": "Pet"},
    {"id": "Shape"},
    {"id": "Circle"},
    {"id": "Square"},
    {"id": "Owner"},
    {"id": "Kennel"},
    {"id": "Club"},
    {"id": "Toy"},
    {"id": "Vet"},
    {"id": "Bowl"},
    {"id": "Food"},
    {"id": "Groomer"},
    {"id": "Clinic"}
  ],
  "relations": [
    {"from": "Dog", "to": "Animal", "kind": "inheritance"},
    {"from": "Dog", "to": "Pet", "kind": "inheritance"},
    {"from": "Circle", "to": "Shape", "kind": "realization"},
    {"from": "Square", "to": "Shape", "kind": "realization"},
    {
      "from": "Owner",
      "to": "Dog",
      "kind": "composition",
      "label": "keeps",
      "from_card": "1",
      "to_card": "many"
    },
    {"from": "Dog", "to": "Kennel", "kind": "composition"},
    {
      "from": "Club",
      "to": "Owner",
      "kind": "aggregation",
      "label": "members",
      "from_card": "0..1",
      "to_card": "*"
    },
    {"from": "Dog", "to": "Toy", "kind": "aggregation"},
    {"from": "Vet", "to": "Dog", "kind": "association", "label": "treats", "directed": true},
    {"from": "Dog", "to": "Bowl", "kind": "association", "directed": true},
    {"from": "Dog", "to": "Food", "kind": "dependency", "label": "eats"},
    {"from": "Dog", "to": "Groomer", "kind": "dependency"},
    {"from": "Vet", "to": "Clinic", "kind": "association"}
  ]
}

Draw it yourself

diago render mermaid-class.mmd > mermaid-class.svg

Open it in the playground to edit it in your browser.