a slight change to an example

this is an example of a triaxial shear test

from yade import pack,plot,qt,export
IsoSigma = -100.
O.periodic=True

# define material
idSand=O.materials.append(FrictMat(young=100e3,poisson=1.,frictionAngle=radians(20),density=2650,label='sand'))

# create particles
sp1=pack.SpherePack()
sp1.makeCloud(maxCorner=(0.02, 0.02, 0.02), psdSizes=[0.00017, 0.000191, 0.0002285, 0.00026, 0.000292, 0.000325, 0.00035], psdCumm=[0.0, 0.1, 0.3, 0.5, 0.6, 0.9, 1], periodic=True,num=5000,seed=1)
sp1.toSimulation(color=(0,0,1),material=idSand)

#### show how to use makeClumpTemplate():

#dyad:
relRadList1 = [1,1]
relPosList1 = [[0.4,0,0],[-0.4,0,0]]

#peanut:
#relRadList2 = [.5,1,.5]
#relPosList2 = [[1,0,0],[0,0,0],[-1,0,0]]

#stick:
#relRadList3 = [1,1,1,1,1]
#relPosList3 = [[0,1,0],[0,2,0],[0,3,0],[0,4,0],[0,5,0]]

templates= []
templates.append(clumpTemplate(relRadii=relRadList1,relPositions=relPosList1))
#templates.append(clumpTemplate(relRadii=relRadList2,relPositions=relPosList2))
#templates.append(clumpTemplate(relRadii=relRadList3,relPositions=relPosList3))

#### show how to use replaceByClumps():
#replace by 50% dyads, 30% peanuts and 10% sticks:
O.bodies.replaceByClumps(templates,[1.],discretization=10)
O.engines=[
 ForceResetter(),
 InsertionSortCollider([Bo1_Sphere_Aabb()]),
 InteractionLoop(
  [Ig2_Sphere_Sphere_ScGeom()],
     [Ip2_FrictMat_FrictMat_FrictPhys()],
     [Law2_ScGeom_FrictPhys_CundallStrack()]),
# PyRunner(command='fabric()',iterPeriod=10000),
        GlobalStiffnessTimeStepper(),
 NewtonIntegrator(damping=0.2),
 PeriTriaxController( goal=(IsoSigma,IsoSigma,IsoSigma), # Vector6 of prescribed final values
    stressMask=7,
    dynCell=True,
    maxStrainRate=(3.e+0,3.e+0,3.e+0),
    maxUnbalanced=0.0001,
    relStressTol=1.e-3,
    doneHook='Finished()',
    label='p3d'
 ),
# VTKRecorder(fileName='3d-vtk-',recorders=['all'],iterPeriod=10000),
# PyRunner(command='strains()',iterPeriod=10000),
# PyRunner(command='balls()',iterPeriod=10000),
 #PyRunner(command='plotAddData()',iterPeriod=100),
]

'''
def plotAddData():
 plot.addData(
  iter=O.iter,iter_=O.iter,
  sxx=p3d.stress[0],syy=p3d.stress[1],szz=p3d.stress[2],
  exx=O.cell.size[0],eyy=O.cell.size[1],ezz=O.cell.size[2],
  Z=avgNumInteractions(),
  Zm=avgNumInteractions(skipFree=True),
                poros=porosity(),
# poros=voxelPorosity(500,(0,0,0),O.cell.size),
  unbalanced=utils.unbalancedForce(),
  t=O.time,
  gWork=O.energy['gravWork'],
  Ep=O.energy['elastPotential'],
  Edamp=O.energy['nonviscDamp'],
  Ediss=O.energy['plastDissip'],
  Ekin=utils.kineticEnergy(),
        Etot=O.energy.total(),**O.energy

 )
 plot.saveDataTxt('macroFile',vars=('t','exx','eyy','ezz','sxx','syy','szz','Z','Zm','poros'))
 plot.saveDataTxt('energyFile',vars=('t','Etot','unbalanced','gWork','Edamp','Ekin'))

O.trackEnergy=True

# plotting
plot.live=True
plot.plots={'iter':('sxx','syy','szz'),'iter_':('exx','eyy','ezz'), ' iter':('unbalanced'),
     #energy plot
            ' iter ':(O.energy.keys,None,'Etot')
}

def fabric():
 fileNomb='fabric'+str(O.iter)
 f = open(fileNomb,'w')
 f.write('id1 id2 x_cp y_cp z_cp n_x n_y n_z Fn_x Fn_y Fn_z Fs_x Fs_y Fs_z ovp\n')
 for i in O.interactions:
  if not i.isReal: continue
  tacts = i.geom.contactPoint
  nmls = i.geom.normal
  ovp = i.geom.penetrationDepth
  Fn = i.phys.normalForce
  Fs = i.phys.shearForce
  f.write('%-16d %-16d %-16g %-16g %-16g %-16g %-16g %-16g %-16g %-16g %-16g %-16g %-16g %-16g %-16g\n'%(i.id1,
      i.id2,tacts[0],tacts[1],tacts[2],nmls[0],nmls[1],nmls[2],Fn[0],Fn[1],Fn[2],Fs[0],Fs[1],Fs[2],ovp))
 f.close

def balls():
 fileCalled='ball'+str(O.iter)
 export.text(fileCalled)

def strains():
 fileNome='strain'+str(O.iter)
 f = open(fileNome,'w')
 f.write('b.id velx vely velz rotx roty rotz\n')
 for b in O.bodies:
  if isinstance(b.shape,Sphere):
   vels = b.state.vel
   rots = b.state.rot()
   f.write('%-16d %-16g %-16g %-16g %-16g %-16g %-16g\n'%(b.id, vels[0],vels[1],vels[2],
       rots[0],rots[1],rots[2]))
 f.close
'''
def Finished():
 O.save('isotropicState.xml')
 print('Finished')
 print(porosity())
 O.pause()

O.run()
#plot.plot(subPlots=True)

how can I change the particles from circular to ellipse？