Could you improve this paragraph clearly and simply?

Sounds perfect to me.

( Where can someone go to buy one of these things ?? )

Yes

Tom’s designs combine Modernist streamlining with the honest construction of the Arts and Crafts Movement. These concepts have influenced Han’s designs. Take the Normadie Water Pitcher made by Peter-Munk in 1935 (Figure 3). the designer integrates a handle and pitcher lid, and it forms a streamlined right angled design. These elements underline transitions, as well as a contrast (Gorman, 2003). Another design showing this (streamlining?) is Hall Chair designed by A.W.N. Pugin c1840 (Figure 4). His concept of this design reflects reduction (Petty, 2015). Pugin uses a simple image and succinct lines to modify this chair thus the design highlights the honesty of its construction.

Tom’s designs combine the streamline conception of Modernism with the honesty of the construction of the Arts and Crafts Movement. These concepts have influenced Han’s designs. In the right angle of this design, it is the [see comment at very bottom] Normadie Water Pitcher made by Peter-Munk in 1935 (Figure 3). The designer integrates a handle and pitcher lid, and it forms a streamline. These elements underline transitions as well as a contrast (Gorman, 2003). Another design is Hall Chair designed by A. W. N. Pugin in approximately 1840 (Figure 4). His concept of this design reflects reduction (Petty, 2015). Pugin merely uses a simple image and succinct lines to modify this chair; thus, the design closely highlights the honesty of construction.

Additions that were not bolded:
-Line 3: Added two spaces between “designs.” and “In”, since it’s the start of a new sentence.
-Line 6: Added spaces between A., W., & N. I assumed it was the guy’s initials, in which case you would space them out.

Comment at very bottom: do you mean the right side? I’m not sure what the “right angle of the design” is.

Also, Is Peter-Munk someone’s last name? I’m not sure what comes before this paragraph, but generally when referring to people, you start by initially writing out their whole name and then just referring to their last name any time after. I prefer always referring to their full name as I would hate to be referred to by just my last name, but that’s just my two cents, not the “professional” way.

Why are you still using the word “streamline” as a noun and adjective?
Streamline is a verb, or if you need an adjective it’s ‘streamlined’.
Where you need a noun it’s maybe a streamlined look or smooth line.

Tom’s designs combine the streamline conception of Modernism with the honesty of construction of the Arts and Crafts Movement.

“Tom’s designs combine Modernism’s sleek streamlining with the honest construction of the Arts and Crafts Movement.”

Gibberish follows. Who is Hans, and where does he figure? Tom, Hans, and The Normandie Water Pitcher made by Peter-Munk have no tie in the paragraph, unless the Normandie pitcher is cited as Modernism? Given that the Arts and Crafts movement was 1880–1910, the hall chair designed by A.W.N. Pugin certainly is not an example of A&C. There is no apparent coherency or flow.

Quite simply, it’s not a paragraph, but a jumbled string (or copy-paste?) of sentences.