Question: Czechoslovakia built a prototype derived from a BH-21 in 1926, what is its models hallmarks?

Context articles: Prototype
Fighter aircraft
Avia BH-33
Avia BH-22
Avia BH-23
Avia BH-19
SNECMA Atar 101
AGO C.III
Protofour
Aero L-60 Brigadýr

A prototype is an early sample, model, or release of a product built to test a concept or process or to act as a thing to be replicated or learned from.
 It is a term used in a variety of contexts, including semantics, design, electronics, and software programming.
 A prototype is generally used to evaluate a new design to enhance precision by system analysts and users.
 Prototyping serves to provide specifications for a real, working system rather than a theoretical one.
 In some design workflow models, creating a prototype (a process sometimes called materialization) is the step between the formalization and the evaluation of an idea.
A fighter aircraft is a military aircraft designed primarily for air-to-air combat against other aircraft, as opposed to bombers and attack aircraft, whose main mission is to attack ground targets.
 The hallmarks of a fighter are its speed, maneuverability, and small size relative to other combat aircraft.
The Avia BH-33 was a biplane fighter aircraft built in Czechoslovakia in 1927.
 It was based on the BH-21J which demonstrated promising results by combining the original BH-21 airframe with a licence-built Bristol Jupiter radial engine.
 Other than the peculiar Avia hallmark of having an upper wing with a shorter span than the lower, it was utterly conventional, even featuring a tail fin for the first time in a Pavel Beneš and Miroslav Hajn design (previous aircraft had a rudder but no fin).
The Avia BH-22 was a trainer aircraft built in Czechoslovakia in 1925, based on the BH-21 fighter.
 A smaller engine was used and armament removed.
 The lighter engine required the wing stagger to be decreased.
 No significant modifications were made to the airframe structure, reduced weight further increasing the ultimate load factor (the BH-21 was designed to 12.5g).
 Some aeroplanes carried a camera gun.
 The type saw long service as a special aerobatic trainer and eventually several examples found their way into Czechoslovakia's aero clubs.
The Avia BH-23 was a prototype night fighter aircraft built in Czechoslovakia in 1926.
 The design was derived from the BH-21 day fighter, incorporating structural changes made to the BH-22 trainer, and the type was originally designated BH-22N.
 Searchlights and other night-flying equipment were added, but the Czechoslovak Air Force were not interested in the project and no sale resulted.
The Avia BH-19 was a fighter aircraft built in Czechoslovakia in 1924.
 It was a low-wing braced monoplane derived from the Avia BH-3 and reflected its designers' ongoing belief that the monoplane configuration was the most suitable for a fighter aircraft.
 Initial trials revealed excellent performance, but also displayed control problems and aileron flutter.
 Nevertheless, the Czechoslovakian Army was sufficiently impressed to inform Avia that it would order the BH-19 if the problems could be rectified.
 The first prototype was destroyed in a crash during speed trials, and the second prototype revealed no better handling than its predecessor.
 At this point, the Czechoslovakian War Ministry stepped in and asked Avia to cease its attempts to develop a monoplane fighter.
The SNECMA ATAR 101 is a French axial-flow turbojet engine built by SNECMA.
 It was derived from engines and design work carried out at BMW in Germany during World War II, and extensively developed though a progression of more powerful models.
 The name is derived from its original design group, Atelier Technique Aéronautique de Rickenbach employing Herman Östrich and many of the wartime BMW gas turbine design group as well as other German engine design teams.
 The ATAR 101 powered many of the French post-war jet aircraft, including the Vautour II, Étendard IV, Super Mystère B2, and the Mirage III-001, prototype of the Mirage III series.
The AGO C.III was a German reconnaissance biplane of World War I.
 It was a single experimental prototype derived from the manufacturer's C.I design.
Protofour or P4 is a set of standards for model railways allowing construction of models to a scale of 4 mm to 1 foot (1:76.2), the predominant scale of model railways of the British prototype.
 For historical reasons almost all manufacturers of British prototype models use 00 gauge (1:76.2 models running on gauge track).
 There several finescale standards which have been developed to enable more accurate models than 00, and P4 is the most accurate in common use.
The Aero L-60 Brigadýr (Czech: "Brigadier" ) was a small, high-wing propeller-driven Czechoslovakian STOL utility aircraft developed for both civil and military use.
 A prototype, designated XL-60, with Argus As 10C engine, first flew on December 24, 1953, but it was not successful.
 The plane was thoroughly redesigned and the second improved prototype, with M-208B flat-six engine, flew on June 8, 1954.
 The aircraft's configuration bears a strong resemblance to the Fieseler Fi 156 "Storch" licence-produced in Czechoslovakia during and after World War II (as K-65 Čáp), and which this aircraft was intended to replace.
 By the end of production in 1960, 273 had been built by Aero, including an improved version, the L-160 with an all-metal tail.