graph TD
    P1["Post. 1\nDraw a straight line from any po..."]
    P2["Post. 2\nProduce a finite straight line c..."]
    P3["Post. 3\nDescribe a circle with any cente..."]
    P4["Post. 4\nAll right angles equal one another"]
    P5["Post. 5\nParallel postulate: if interior ..."]
    CN1["CN 1\nThings equal to the same thing a..."]
    CN2["CN 2\nIf equals are added to equals, t..."]
    CN3["CN 3\nIf equals are subtracted from eq..."]
    CN4["CN 4\nThings coinciding with one anoth..."]
    CN5["CN 5\nThe whole is greater than the part"]
    Prop1["Prop. I.1\nEquilateral triangle on given line"]
    Prop2["Prop. I.2\nPlace line equal to given at point"]
    Prop3["Prop. I.3\nCut off from greater segment equal to less"]
    Prop4["Prop. I.4\nSAS congruence"]
    Prop5["Prop. I.5\nBase angles of isosceles equal"]
    Prop7["Prop. I.7\nUniqueness of triangle from ends"]
    Prop8["Prop. I.8\nSSS congruence"]
    Prop9["Prop. I.9\nBisect angle"]
    Prop10["Prop. I.10\nBisect line"]
    Prop11["Prop. I.11\nPerpendicular from point on line"]
    Prop12["Prop. I.12\nPerpendicular from point not on line"]
    Prop13["Prop. I.13\nAngles on line sum to two right"]
    Prop14["Prop. I.14\nIf angles sum to two right, straight line"]
    Prop15["Prop. I.15\nVertical angles equal"]
    Prop16["Prop. I.16\nExterior angle > interior opposite"]
    Prop17["Prop. I.17\nSum of two angles < two right"]
    Prop18["Prop. I.18\nAngle opposite greater side greater"]
    Prop19["Prop. I.19\nSide opposite greater angle greater"]
    Prop20["Prop. I.20\nTriangle inequality"]
    P1 --> Prop1
    P3 --> Prop1
    Prop1 --> Prop2
    P1 --> Prop2
    P2 --> Prop2
    P3 --> Prop2
    Prop2 --> Prop3
    P3 --> Prop3
    CN4 --> Prop4
    CN5 --> Prop4
    Prop3 --> Prop5
    Prop4 --> Prop5
    Prop5 --> Prop7
    Prop7 --> Prop8
    Prop1 --> Prop9
    Prop3 --> Prop9
    Prop8 --> Prop9
    Prop1 --> Prop10
    Prop4 --> Prop10
    Prop9 --> Prop10
    Prop1 --> Prop11
    Prop3 --> Prop11
    Prop8 --> Prop11
    Prop8 --> Prop12
    Prop10 --> Prop12
    Prop11 --> Prop13
    Prop13 --> Prop14
    Prop13 --> Prop15
    Prop3 --> Prop16
    Prop4 --> Prop16
    Prop10 --> Prop16
    Prop15 --> Prop16
    Prop13 --> Prop17
    Prop16 --> Prop17
    Prop3 --> Prop18
    Prop5 --> Prop18
    Prop16 --> Prop18
    Prop5 --> Prop19
    Prop18 --> Prop19
    Prop3 --> Prop20
    Prop5 --> Prop20
    Prop19 --> Prop20
    classDef postulate fill:#e74c3c,color:#fff,stroke:#c0392b
    classDef commonNotion fill:#9b59b6,color:#fff,stroke:#8e44ad
    classDef proposition fill:#1abc9c,color:#fff,stroke:#16a085
    class P1,P2,P3,P4,P5 postulate
    class CN1,CN2,CN3,CN4,CN5 commonNotion
    class Prop1,Prop2,Prop3,Prop4,Prop5,Prop7,Prop8,Prop9,Prop10,Prop11,Prop12,Prop13,Prop14,Prop15,Prop16,Prop17,Prop18,Prop19,Prop20 proposition