import bpy
import math


def staircase(name, nSteps, r1, r2, dTheta,dz):
    verts=[]
    faces = []
    for i in range(nSteps):
        v3=i*4
        v1 = v3-2
        v2 = v3-1
        v4 = v3+1
        v5 = v3+2
        v6 = v3+3
        theta = i*dTheta
        z= i*dz
        c = math.cos(theta)
        s = math.sin(theta)
        verts.append( [r1*c, r1*s, z] )
        verts.append( [r2*c, r2*s, z] )
        verts.append( [r1*c, r1*s, z+dz] )
        verts.append( [r2*c, r2*s, z+dz] )
        if (0!=i):
            faces.append( [v1, v2, v4, v3] )
        faces.append( [v3, v4, v6, v5] )
    mesh = bpy.data.meshes.new(name);
    mesh.from_pydata(verts, [], faces)
    mesh.validate(True)
    mesh.show_normal_face = True
    
    obj = bpy.data.objects.new(name, mesh)
    scn = bpy.context.scene
    scn.objects.link(obj)



staircase("stairs", 40, 0.2, 2, math.pi/10, 0.2)