[Question] What's that trick...

    call SetUnitPositionLoc( peasant, PolarProjectionBJ(GetRectCenter(some_region), 500.00, 90.00) )

function PolarProjectionBJ takes location source, real dist, real angle returns location
    local real x = GetLocationX(source) + dist * Cos(angle * bj_DEGTORAD)
    local real y = GetLocationY(source) + dist * Sin(angle * bj_DEGTORAD)
    return Location(x, y)
endfunction

globals
    constant real height = 100. // height at launch
    constant real speed = 900. // speed
    constant real distance = 3000. // how far it will travel
    constant real timestep = 0.033 // how fast to update
    real missile_x
    real missile_y
    real missile_z // "true" x, y, z in relation to wc3's 3d space (not terrain)
    real missile_dist
    real missile_x_comp
    real missile_y_comp // x and y component of velocity (so you don't have to re-calculate)

    unit missile_unit

    location locZ = Location (0., 0.) // Used for custom function GetLocZ()
endglobals

function GetLocZ takes real x, real y, returns real
    call MoveLocation(locZ, x, y) // moving is faster than creating a new location and then destroying it
    return GetLocationZ(locZ)
endfunction

function callback takes nothing returns nothing
    local real z
    set missile_x = missile_x + missile_x_comp
    set missile_y = missile_y + missile_y_comp
    call SetUnitX(missile_unit, missile_x)
    call SetUnitY(missile_unit, missile_y)
    set z = missile_z - GetLocZ(missile_x, missile_y) // the flying height of the unit is the height after the terrain (to keep it in 3d space)
    call SetUnitFlyHeight(missile_unit, z, 0) // set the height of the unit
    set missile_dist = missile_dist + speed*timestep // add the distance traveled per time-step
    if missile_dist >= distance then // travelled the distance required
        call RemoveUnit(missile_unit)
        set missile_dist = 0
        set missile_x_comp = 0
        set missile_y_comp = 0 // set the "missile" to null
        call DestroyTimer(GetExpiredTimer())
    endif
endfunction

function Launch takes real x, real y, real angle returns nothing
    if missile_x_comp == 0 and missile_y_comp == 0 then
        return // already a missile
    endif
    // we want the x and y components.  To get them, we need trig ratios.
    // the angle and speed create a terminal arm at the origin of x, y
    // we want to find the x1, and y1 cord at the end of the arm; they are called components
    // no matter which way the arm is pointing, the x and y components will make a right angle on the x axis.
    // since this is true, we can use "SOH CAH TOA" to find the x and y components
    // since X is "opposite" of the angle, it uses Sin
    // since Y is "adjacent" of the angle, it uses Cos
    set missile_x_comp = speed*timestep*Cos(angle*bj_DEGTORAD) // convert the angle to rad, since thats what the native uses
    set missile_y_comp = speed*timestep*Sin(angle*bj_DEGTORAD)
    
    set missile_x = x
    set missile_y = y
    set missile_z = height + GetLocZ(x, y) // its initial height is 100 over the current terrain height (z then becomes the "true" height of the object, in relation to wc3's 3d space)
    set missile_unit = CreateUnit(Player(0), 'hfoo', x, y, 0.)
    call SetUnitX(missile_unit, x) //to make sure it appears there
    call SetUnitY(missile_unit, y) // same thing again
    call UnitAddAbility(missile_unit, 'Amrf') // add crow form (I hope id is correct)
    call UnitRemoveAbility(missile_unit, 'Amrf')
    call SetUnitFlyHeight(missile_unit, height, 0) // set fly height to initial height since it is already correct with out getlocz call, to the terrain.
    call TimerStart(CreateTimer(), timestep, true, function callback)
endfunction