public float[] nextVertex() {
    if (vertexCount == vertices.length) {
      //parent.message(CHATTER, "re-allocating for " +
      //             (vertexCount*2) + " vertices");
      float temp[][] = new float[vertexCount<<1][PGraphics.VERTEX_FIELD_COUNT];
      System.arraycopy(vertices, 0, temp, 0, vertexCount);
      vertices = temp;

      r   = new float[vertices.length];
      dr  = new float[vertices.length];
      l   = new float[vertices.length];
      dl  = new float[vertices.length];
      sp  = new float[vertices.length];
      sdp = new float[vertices.length];
    }
    return vertices[vertexCount++];  // returns v[0], sets vc to 1
  }