Incidence matrix according to Dynkin symbol

s3s4s5*a   (N → ∞)

demi( . . .    ) | 60N |   2   2   2 |   1   1   1   3
-----------------+-----+-------------+----------------
sefa( s3s .    ) |   2 | 60N   *   * |   1   0   0   1
sefa( s . s5*a ) |   2 |   * 60N   * |   0   1   0   1
sefa( . s4s    ) |   2 |   *   * 60N |   0   0   1   1
-----------------+-----+-------------+----------------
      s3s .      ♦   3 |   3   0   0 | 20N   *   *   *
      s . s5*a   ♦   5 |   0   5   0 |   * 12N   *   *
      . s4s      ♦   4 |   0   0   4 |   *   * 15N   *
sefa( s3s4s5*a ) |   3 |   1   1   1 |   *   *   * 60N

starting figure: x3x4x5*a