Macaulay shows that two scrolls have exactly the same closure.

First consider the 3 morphisms A^2 -> A^6
phi(1): (s1,s2) -> (s1,0,0,s2,0,0)
phi(2): (s1,s2) -> (0,s1,0,0,s2,0)
phi(3): (s1,s2) -> (0,0,s1,0,0,s2)

o7 shows that the ideal of the scroll of these three morphisms is
generated by the 2 by 2 minors of 
y1 y2 y3
y4 y5 y6

Then consider the 2 morphisms A^3 -> A^6
Phi(1): (r1,r2,r3) -> (r1,r2,r3,0,0,0)
Phi(2): (r1,r2,r3) -> (0,0,0,r1,r2,r3)

o12 shows that the ideal of this scroll is exactly the same as the ideal of the above scroll.

Macaulay 2, version 1.1
with packages: Classic, Core, Elimination, IntegralClosure, LLLBases, Parsing, PrimaryDecomposition, SchurRings, TangentCone

i1 : QQ[s1,s2,t1,t2,t3,y1,y2,y3,y4,y5,y6,MonomialOrder => {GRevLex=>5, GRevLex=>6}]

o1 = QQ [s1, s2, t1, t2, t3, y1, y2, y3, y4, y5, y6]

o1 : PolynomialRing


i6 : ideal{t1+t2+t3-1,y1-t1*s1,y2-t2*s1,y3-t3*s1,y4-t1*s2,y5-t2*s2,y6-t3*s2}

o6 = ideal (t1 + t2 + t3 - 1, - s1*t1 + y1, - s1*t2 + y2, - s1*t3 + y3, - s2*t1 + y4, - s2*t2 + y5, - s2*t3 + y6)

o6 : Ideal of QQ [s1, s2, t1, t2, t3, y1, y2, y3, y4, y5, y6]

i7 : gens gb o6

o7 = | y3y5-y2y6 y3y4-y1y6 y2y4-y1y5 t3y4+t3y5+t3y6-y6 t3y1+t3y2+t3y3-y3 t2y6-t3y5 t2y4+t2y5+t3y5-y5 t2y3-t3y2 t2y1+t2y2+t3y2-y2 t1+t2+t3-1
     ----------------------------------------------------------------------------------------------------------------------------------------
     s2-y4-y5-y6 s1-y1-y2-y3 |

                                                             1                                                       12
o7 : Matrix (QQ [s1, s2, t1, t2, t3, y1, y2, y3, y4, y5, y6])  <--- (QQ [s1, s2, t1, t2, t3, y1, y2, y3, y4, y5, y6])

i8 : QQ[r1,r2,r3,t1,t2,y1,y2,y3,y4,y5,y6,MonomialOrder => {GRevLex=>5, GRevLex=>6}]

o8 = QQ [r1, r2, r3, t1, t2, y1, y2, y3, y4, y5, y6]

o8 : PolynomialRing


i11 : ideal{t1+t2-1,y1-t1*r1,y2-t1*r2,y3-t1*r3,y4-t2*r1,y5-t2*r2,y6-t2*r3}

o11 = ideal (t1 + t2 - 1, - r1*t1 + y1, - r2*t1 + y2, - r3*t1 + y3, - r1*t2 + y4, - r2*t2 + y5, - r3*t2 + y6)

o11 : Ideal of QQ [r1, r2, r3, t1, t2, y1, y2, y3, y4, y5, y6]

i12 : gens gb o11

o12 = | y3y5-y2y6 y3y4-y1y6 y2y4-y1y5 t2y3+t2y6-y6 t2y2+t2y5-y5 t2y1+t2y4-y4 t1+t2-1 r3-y3-y6 r2-y2-y5 r1-y1-y4 |

                                                              1                                                       10
o12 : Matrix (QQ [r1, r2, r3, t1, t2, y1, y2, y3, y4, y5, y6])  <--- (QQ [r1, r2, r3, t1, t2, y1, y2, y3, y4, y5, y6])

i13 :