Heartfelt tributes were paid last night to one of Scotland's most idiosyncratic and beloved artists, writer and sculptor George Wyllie, who has died at the age of 90.

Friends, artists and admirers of the creator of the Straw Locomotive, the Running Clock and the Paper Boat – famous artworks that combined humour, wry social comment and a sense of the spectacular – praised his unique and "fearless" talents.

Wyllie, whose life and work is being celebrated in a year-long festival, died in Inverclyde Royal Hospital in Greenock after being taken ill earlier this week.

Louise Wyllie, his elder daughter, said: "He really did live a life less ordinary. There was no-one else like him, and I suspect there never will be.

"My father was delighted at all the developments which the Friends of George Wyllie have made in the last year in establishing his legacy. He was delighted about the latest news which will see us putting his life and work into the curriculum in Scottish schools and working with skilled shipyard workers in Inverclyde on the creation of giant question marks."

Wyllie, born in Shettleston, Glasgow, in 1921, began his artistic life after service in the Royal Navy – including a life-changing visit to Hiroshima – and work as a customs and excise officer in Gourock. He wrote plays, produced sculptures, and inspired a generation of Scottish artists, writers, actors and filmmakers.

Ms Wyllie said: "He was so pleased with the idea of The Whysman Festival, which is running throughout 2012 to celebrate his artistic legacy, and just a couple of months ago he attended a small pre-opening party for the festival at The Collins Gallery for his archive exhibition, A Life Less Ordinary. I am so glad he saw the start of what is a year of celebration."

Wyllie, whose wife Daphne died in 2004, is survived by daughters Louise Wyllie and Elaine Aitken, as well as grandsons, Calvin and Lewis, and granddaughter, Jennifer. He had been living in a care home in Greenock since last year.

Much of Wyllie's work was donated to Strathclyde University five years ago.

The Friends of George Wyllie is still in talks with the National Galleries of Scotland (NGS) about his work being represented in the national collections.

Simon Groom, the director of modern and contemporary art at the NGS, said: "We are very sad to hear of the death of a unique talent, a distinctive voice of fearlessness that is an ideal for any artist. His Paper Boat is now considered one of the classics."

First Minister Alex Salmond said Wyllie was an "extraordinary artist whose work touched the lives of generations of Scots and will be familiar to many generations to come".

Wyllie described himself as a "scul?tor" because he said the question mark was too important to be left to the end.

Jan Patience, chairwoman of the Friends of George Wyllie, said: "He was a remarkable artist, he had the knack of making you ask questions, of not accepting the status quo. His mind was constantly enquiring, and his art was constantly pushing out barriers. That is his legacy."

Karin Currie, president of the Royal Glasgow Institute of the Fine Arts, said: "George was special. He was so irreverential of art forms and yet embraced so many with his unique humour and irrepressible passion."

Murray Grigor, the Scottish filmmaker, said: "Wyllie's public art was an inspiration to a whole new generation of Glasgow artists, such as Douglas Gordon, Rory Buchanan and Christine Borland."

His award-winning play about world banking, A Day Down a Goldmine, was produced several times throughout the 1980s.

Most famously, his Paper Boat sailed from Glasgow to New York and back to Scotland, making the front page of the Wall Street Journal when it berthed in New York in 1990.