Let's face it: pets are no longer just pets, but rather increasingly demanding members of the family, with their own needs and proclivities. And in tight urban living spaces like Hong Kong, pet-inclusive design has particular challenges to take on.
When architect Greg Pearce and his partner knocked their flat into an open-plan layout, it suited their two cats well. But the one remaining barrier, a sliding mirrored partition between the bedroom and the living space, wasn't so popular.
"The cats like to sleep with us, so the problem was how to let them, while still making sure they could access their food and the bathroom when we wanted to close the door," says Pearce, an architect with Hong Kong-based studio, One Space.
Appraising the layout, Pearce decided to cut short a column of tinted glass partitioning.
He fitted the gap with a light Perspex flap on a pivot and a little pop lock, and gave the cats their own personal (but lockable) entrance. "It was dead simple," he says. "Not many architects think about designing specifically for cats, but anyone designing a flat these days will think about the way that all the inhabitants use it."
Pets are registering increasingly on the radars of interior and product designers, with 'less is more' as their mantra. Take Akemi Tanaka-Blanchard, a furniture designer in New York who has found a keen following for her Curve cat ledge.
The slim wall-mounted bed - a single piece of wood - is a space saver that provides cats with sleep and play space somewhere other than under-foot.
Tanaka-Blanchard offers it in a variety of finishes with snap-on cushions in a range of colours and fabrics, which means that it can be unobtrusive, or an eye-catching addition to a room. "I do think the pet design industry is growing here and abroad," says the designer, though she notes that this has taken some time.
"Curve is the result of my own frustration with pet products currently on the market," she adds. "I could not find furniture for my cats that would mesh with my own [and] not scream crazy cat lady. Curve was designed for pet owners who aren't willing to sacrifice style."
A broad range of innovations on the pet-perch theme are now on the market for design-conscious owners, some doubling as climbable ledges leading to high-level cat flaps (for upper floors with access to exterior ledges for example), others simply providing snooze nooks - but all with a chic aesthetic.
Some serve multiple purposes for pets and their owners. Suffering from a surplus of books and cats? Look no further than Urban Cats' Cat Case - a canny bookshelf and cat tree in one. Pets get to climb inside and between shelves to an upper-level lookout, and are kept separately from the books. Fitted carpet lining prevents them from sharpening claws on the wooden interior.
A notable pioneer has been Wen Liu. Based in the UK, Liu started his company Pet Dream House to generate affordable products for furry family members. Networking among designers, he opens their designs to votes on his website - then works with manufacturers and retailers to produce and sell the most popular.
"This is an area that needs innovation at the moment," he said. "Pet furniture and products need to advance at the same pace at which our home furnishings and leisure products do."
Among the designs for sale at petdreamhouse.com  is Lollipop by Onur Ozkaya, a London-based industrial design studio known for its rather space-age ergonomics. In red, black or white fibreglass, the free-standing cat pod gives cats a comfy lookout, and homes a unique design feature.
Elsewhere, designers have begun to tackle less glamorous pet problems, such as the unsightliness of litter and food mess. Pet feeding stations are being discreetly built into kitchen cabinets to hide mess. Litter trays are being camouflaged and better concealed, with a range of materials to soak up liquid and smell.
At US$2,200 the Kattbank, for example, handily doubles as a bench while hiding a litter cubby in its bowels. And others, such as Dijeau Poage Construction have tackled pet bath-time escapades. One recent design includes shower units with pull-out stairs and door panels
"Design is becoming much more prevalent in everyday life for all people," says Tanaka-Blanchard. "Well designed and aesthetically-pleasing pet products are a natural extension of this evolution."
Sometimes it's the savvy owners themselves who are commissioning or constructing solutions for their pets. One dog lover in Sai Kung addressed her German Shepherd's hip dysplasia by having Keith Chan of Hintegro design an anti-slip ramp up the 10 steps to her house. The cost of having the steel ramp custom built, however, made her baulk: estimates came in at about HK$10,000.
A Hong Kong vet, Andy Pilling, couldn't find anything on the market to match his home interior, so he designed unobtrusive but attractive cat scratching posts with sleep spaces in his lounge, along with a cat shelf in his study, and a scratch wall in the bedroom.
His contractor, who was in the middle of renovating his apartment, agreed to build each for the cost of a few hundred Hong Kong dollars. "Cats like to be high up so they can see around them but feel secure," he said. "And I've also noticed that a lot of cat scratching posts on the market are too short. So I built something that would let them stretch out properly."
For one cat-owning couple in Brooklyn, New York, the solution to pet exercise and entertainment was in a fibreboard mini staircase, which they built to wrap around their small apartment, and interact with furniture units as a feline obstacle course.
For Hong Kong-based photographer John Butlin, the avian equivalent was a climbing frame for Marty, an Indian Ringneck parrot, and his budgie, called Budgie. He constructed the frame from bits and pieces he had lying around and clamped it to an existing window frame, close to his desk at home, so both can keep him company while he's working.
"Parrots get stressed and depressed if they are kept for long periods in a cage so I wanted to give him as much freedom as practical to roam about," Butlin says. "Its dimensions from perch to perch match the length from beak to claw, so he can hold on to one and grab the other. It's designed to keep him fit, interested and make him investigate."
For Tanaka-Blanchard, the focus has been inevitable. "Design is becoming much more prevalent in everyday life for all people," she observes. "Well designed and aesthetically pleasing pet products are a natural extension of this evolution."