The following sub creates

1
1
1

Sub test()
Dim b As Workbook
Dim s As Worksheet
Set b = ThisWorkbook
Set s = b.Sheets("Sheet1")
s.Activate
Dim v
v = Array(1, 4, 6)
Dim r As Range
Set r = s.Range(s.Cells(1, 1), s.Cells(3, 1))
r.Value = v
End Sub

When I change the r assignment to

Set r = s.Range(s.Cells1,1),s.Cells(1,3)

I get

1 4 6

What is the logic in Excel that makes it treat horizontal assignments
different from vertical ones?

Thanks.