I wasn’t 100% sure what you asked for, but I crafted something anyways (based on the tutorial link you gave above):

```
using GLMakie
GLMakie.activate!()
################################################################################
# Sliders
################################################################################
# initialize plot
fig = Figure(resolution = (3840, 2160))
# add axis
ax1 = fig[1, 1] = Axis(fig,
# borders
aspect = 1,
# title
title = "Sliders Tutorial",
titlegap = 48, titlesize = 60,
# x-axis
xautolimitmargin = (0, 0), xgridwidth = 2, xticklabelsize = 36,
xticks = LinearTicks(20), xticksize = 18,
# y-axis
yautolimitmargin = (0, 0), ygridwidth = 2, yticklabelpad = 14,
yticklabelsize = 36, yticks = LinearTicks(20), yticksize = 18
)
# darken axes
vlines!(ax1, [0], linewidth = 2)
hlines!(ax1, [0], linewidth = 2)
# create sliders
lsgrid = labelslidergrid!(fig,
["scale", "x-reference", "y-reference"], #edited from original
Ref(LinRange(-10:0.01:10));
formats = [x -> "$(round(x, digits = 2))"],
labelkw = Dict([(:textsize, 30)]),
sliderkw = Dict([(:linewidth, 24)]),
valuekw = Dict([(:textsize, 30)])
)
# set starting position for slope
set_close_to!(lsgrid.sliders[1], 1.0)
# layout sliders
sl_sublayout = GridLayout(height = 150)
fig[2, 1] = sl_sublayout
fig[2, 1] = lsgrid.layout
# draw a function
x = -10:0.01:10
m = @lift($scale .* x.^2) #quadratic function #edited from original
line1 = lines!(ax1, x, m, color = :blue, linewidth = 5) #edited from original
# create listeners
scale = lsgrid.sliders[1].value #edited from original
xreference = lsgrid.sliders[2].value #edited from original
yreference = lsgrid.sliders[3].value #added
# xreference, yreference are Float32s
# but for arrows! below we need vectors of Float32s, so we promote them here
# arrow base points
xbase = @lift([$xreference])
ybase = @lift([$yreference])
#new multi-variable scalar-valued functions
p(x,y,scale) = (x + scale * y-1)^2/(scale^2) #added
z(x,y,scale) = cbrt(-p(x,y,scale)/2) #added
# arrow head points
# note: here we also return vectors
xhead = lift(xreference, yreference, scale) do x, y, s
return [ x/1 + 2*s * z(x,y,s) ]
end
yhead = lift(xreference, yreference, scale) do x, y, s
return [ y + z(x,y,s) ]
end
arrows!(ax1, xbase, ybase, xhead, yhead)
display(fig)
```

The above gives you now the arrow you can control with the sliders. Maybe you need to tune the computation of the end points a bit, because right now it does not seem to make any sense to me

Modifications I made to your code:

- You can’t use
`-`

in variable names, so I renamed `x-reference`

to `xreference`

, etc.
- I replaced
`:fontsize`

with `:textsize`

, because that was changed recently, but you might be running an older version of Makie.
- Arrows can be drawn with
`arrows`

, cf. arrows - Beautiful Makie. For this to work, one has to pass `Vector{Float32}`

(or Observables thereof) to `arrows!`

. Hence, I add an extra `lift`

for that to promote the `xreference, yreference`

. The reason it wants a Vector instead of a single number for each component is that `arrows`

is optimized to draw vector fields, see the link above.

Last remark: Next time please provide a minimal working example (MWE) of the code that is already working and others can then use to build on top off.