Welz Tango - Cased decor

With Franz Welz you see master glass blowing and ingenious productivity. The are examples of Tango from the mid-20's to the mid 30's. I'm not exactly sure about their production methods because these pieces have a rim threading (fire polished) and no pontil mark? Perhaps Craig would be kind enough to link us to how the "gadget" worked or explain how these pieces were produced...

In the decor you see many variations starting with a Tango base color and contrasting rim. I will describe each of the cased decors from top Left to Right

1. Polka dot (powder) decor
2 Line decor
3 Line decor
4 Line and dot decor
5 Three examples of white Bi-color
6 Black Bi-color
7 Orange Bi-color
8 Lime Crackled Adventurine decor
9 Red Crackled Adventurine decor
10 Line pull decor
11 Spoon pull decor
12 Confetti decor
13 Confetti decor
14 Yellow Bi-color
15 Aqua Bi-color