It just needs to be present on the computer. It need not be running but arcpy needs to be imported which means it must be on the computer. gp.Addmessage statements need to be replaced with print statements. The following is an example
'''
CreatePolyDemo.py
Demonstrates calculating various properties for polygons
'''
import arcpy
pnt = arcpy.Point()
triangle = [[0,0],[0,1],[1,0]]
square = [[0,0],[0,1],[1,1],[1,0]]
rectangle = [[0,0],[0,1],[2,1],[2,0]]
polygons = [triangle, square, rectangle]
labels = ["Triangle", "Square", "Rectangle"]
array = arcpy.Array()
polys = []
for i in range(len(polygons)):
a_poly = polygons
print "\n", labels," Coordinates: ", a_poly
for pair in a_poly:
pnt.X = pair[0]
pnt.Y = pair[1]
array.add(pnt)
print " X %20.16f Y %20.16f" % (pnt.X, pnt.Y)
array.add(array.getObject(0))
poly = arcpy.Polygon(array)
print "Polygon properties:"
print " area %20.16f\n length %s" % (poly.area, poly.length)
print " centroid %s\n true centroid %s " % (poly.centroid, poly.trueCentroid)
print " first point %s\n last point %s " % (poly.firstPoint, poly.lastPoint)
print " extent %s " % (poly.extent)
print " hull %s\n " % (poly.hullRectangle)
array.removeAll()
polys.append(poly)