STRIPE_WIDTH = STRIPE_WIDTH or 0.5	-- initialization

-- if the command stripes has already created some stripes, the following function
-- can swap two stripes, given their indeces

function STswap( a, b )
n, x, z = stripes()
if n < 2 or a == nil or b == nil or a > n or a < 1 or b > n or b < 1 or a == b
then return end
xa = x[a]; za = z[a]
x[a] = x[b]; z[a] = z[b]
x[b] = xa; z[b] = za
stripes( n, x, z, STRIPE_WIDTH )
amp()
end

-- this list of arguments of the next function contain as many indexes
-- as the number of existing slices

function STorder(...)
NumSlices, x, z = stripes()
if NumSlices ~= arg.n or NumSlices < 2 then return end
newX = {}
newZ = {}
for i,old in ipairs(arg) do
	newX[i] = x[old]
	newZ[i] = z[old]
end
newX.M = x.M
newZ.M = z.M
stripes( n, newX, newZ, STRIPE_WIDTH )
amp()
end