VisuRiddles: Fine-grained Perception is a Primary Bottleneck for Multimodal Large Language Models in Abstract Visual Reasoning - Yan, Hao; Liu, Xingchen; Wang, Hao; Cao, Zhenbiao; Zheng, Handong; Yin, Liang; Su, Xinxing; Chen, Zihao; Wu, Jihao; Liao, Minghui; WENG, CHAO; Chen, Wei; et al. (International Conference on Learning Representations, 2026)